Choosing the right garbage bag might seem like a simple everyday decision, but the material it is made from matters more than most people realise. Whether you are managing waste at home, running a busy commercial kitchen, or overseeing industrial operations, the type of garbage bag you use affects everything from how well it holds up under pressure to what happens to it once it leaves your bin.
At Plastpack, we have been supplying Australian households and businesses with high-quality bag solutions for decades. In this guide, we break down the three main types of garbage bag materials available in Australia today, what they are made of, how they perform, and which situations they are best suited to.
What Are Garbage Bags Actually Made Of?
Before diving into the three categories, it helps to understand that all garbage bags start with some form of polymer, either derived from fossil fuels, plant-based sources, or a blend of both. The composition of that polymer determines how the bag behaves in use and what happens to it after disposal.
Most garbage bags produced in Australia fall into one of three broad categories: traditional plastic (petroleum-based), biodegradable plastic (additive-modified or bio-based), and certified compostable (plant-derived polymers). Each has a distinct set of strengths, limitations, and environmental implications. Understanding the differences helps you make a purchasing decision that suits your actual needs rather than just the marketing on the box.
1. Traditional Plastic Garbage Bags
What They Are Made Of
The vast majority of standard garbage bags are made from polyethylene, specifically Low-Density Polyethylene (LDPE) or High-Density Polyethylene (HDPE). These are petroleum-derived thermoplastics that are extruded into thin, flexible film and then formed into bag shapes.
LDPE bags are soft, stretchy, and puncture-resistant, making them a popular choice for general household waste. They have a higher tolerance for sharp or irregular objects and are less likely to split under load.
HDPE bags are thinner, stiffer, and slightly more crinkly to the touch. They are cost-effective, strong for their weight, and commonly used in commercial and industrial settings where large volumes of lighter waste need to be managed.
At Plastpack, our garbage bags are manufactured at our Australian facility using premium-grade polyethylene film. Because we control the entire production process in-house, from film extrusion through to bag forming, we maintain tight quality standards across every batch.
Performance and Practicality
Traditional plastic bags are the benchmark against which all alternatives are measured, and for good reason:
Strength and durability: They resist tearing, puncturing, and leaking better than most alternatives at the same thickness.
Moisture resistance: They create a fully waterproof barrier, making them ideal for wet waste, kitchen scraps, and damp environments.
Shelf life: They do not degrade on the shelf, meaning you can store them for years without any loss of performance.
Cost efficiency: Polyethylene bags remain the most affordable option per unit, particularly when purchased in bulk.
Size range: They are available in a very wide range of capacities, from small bin liners through to large industrial garbage bags suited to commercial skip bins and site clean-ups.
Environmental Considerations
Traditional plastic garbage bags carry a significant environmental footprint. They are made from non-renewable fossil fuels, they do not break down in landfill within any practical timeframe, and if they escape into the natural environment, they can persist and fragment into microplastics.
That said, it is worth understanding the full picture. Sending waste to landfill in a well-sealed plastic bag can actually reduce the leaching of liquids into surrounding soil and groundwater compared to loose or poorly contained waste. The problem is less the bag itself and more the volume of single-use plastic waste going to landfill in the first place.
Recycling options for clean polyethylene bags have expanded in Australia through soft plastics drop-off programmes, though these schemes are not universally available and have faced capacity challenges in recent years.
Best Suited For
- General household rubbish bins
- Commercial and office waste collection
- Industrial and construction waste
- Medical and clinical waste (specific grades required)
- Any application where strength and moisture resistance are the top priorities
2. Biodegradable Garbage Bags
What They Are Made Of
The term “biodegradable” is one of the most misunderstood in the packaging industry. In Australia, products labelled as biodegradable are not subject to strict regulation in the same way as certified compostable products, which means there is considerable variation in what this label actually means.
There are two main types of biodegradable garbage bags you will encounter:
Oxo-degradable bags are conventional plastic bags with a pro-oxidant additive mixed in. The additive accelerates the oxidation of the polyethylene when exposed to heat, UV light, and oxygen, causing the plastic to fragment into smaller pieces. Critically, these smaller pieces are still plastic. They do not biodegrade in any meaningful biological sense; they simply break down into microplastics more quickly. Oxo-degradable bags have faced significant criticism from environmental scientists and regulators, and many councils have moved away from endorsing them. If a bag is marketed simply as “degradable” without a certified compostable logo, it is likely oxo-degradable.
Bio-based biodegradable bags are made from plant-derived polymers such as PLA (polylactic acid, derived from corn starch) or blends of bio-based and petroleum-based polymers. Some of these can break down more completely under the right conditions, but they still require specific environments, typically industrial composting facilities with controlled heat and humidity, to do so within a reasonable timeframe.
Performance and Practicality
Biodegradable bags offer a middle ground between traditional plastic and certified compostable options:
Strength: Comparable to standard LDPE bags in most household applications, though some thinner bio-based options may be less puncture-resistant.
Moisture resistance: Most biodegradable bags retain good moisture resistance in the short term, though some bio-based blends can become brittle or soften more quickly in warm or humid conditions.
Shelf life: Oxo-degradable bags have a reasonably long shelf life if stored away from heat and UV. Some bio-based options may have a shorter shelf life than conventional plastic.
Cost: Generally more expensive than standard polyethylene bags, with the price premium varying considerably depending on the formulation.
The Certification Question
Because the term “biodegradable” is not tightly regulated in Australia, the best advice when buying biodegradable bags is to look for third-party certification. Organisations such as the Australasian Bioplastics Association (ABA) and international bodies like TUV Austria issue certifications that verify a product’s claims under defined test conditions. Without certification, it is very difficult for a consumer or business to know whether a bag marketed as biodegradable will actually biodegrade in practice.
Environmental Considerations
The environmental credentials of biodegradable bags are complicated. The headline claim of being “better for the environment” often depends heavily on end-of-life conditions that are difficult to control in practice. Oxo-degradable bags that fragment into microplastics in landfill or the environment may cause as much harm as conventional plastic, possibly more. Bio-based bags that end up in landfill rather than an industrial composting facility may not biodegrade significantly faster than conventional plastic, as most modern landfills are not designed to accelerate biological breakdown.
The environmental benefit of biodegradable bags is most realised when they are used specifically for organic waste that will be diverted to an appropriate composting or processing facility.
Best Suited For
- Households and businesses transitioning away from conventional plastic
- Applications where certified compostable bags are not yet available or practical
- Use with green-waste collection services that accept certified biodegradable bags (always check with your local council first)
- Office and light commercial settings where the bag will rarely be exposed to prolonged heat or moisture
3. Compostable Garbage Bags
What They Are Made Of
Certified compostable garbage bags are made from plant-derived polymers that are designed to break down completely through biological processes into water, carbon dioxide, and biomass. Common base materials include:
PLA (Polylactic Acid): Made from fermented plant starch, typically corn. PLA is rigid and clear in its standard form but can be blended to create more flexible film suitable for bags.
PBAT (Polybutylene Adipate Terephthalate): A biodegradable co-polymer often blended with PLA or starch to improve flexibility and tear resistance.
Thermoplastic starch (TPS): Derived from potato, corn, or cassava starch, often blended with other polymers.
Most commercial compostable bags use a blend of the above materials to achieve the right balance of strength, flexibility, and compostability.
The Certification Standards
In Australia, the key certification to look for on compostable bags is the Australian Standard AS 4736, which covers compostability in industrial or commercial composting facilities. Some products also carry certification to AS 5810, which relates to home composting conditions and requires breakdown at lower temperatures. The ABA’s seedling logo is a widely recognised mark on packaging that indicates compliance with these standards.
Performance and Practicality
Compostable bags have improved substantially in quality over the past decade, but they still come with performance trade-offs compared to conventional plastic:
Strength: Modern compostable bag blends offer good strength for light to moderate household waste, but they are generally less tolerant of sharp objects, heavy loads, or prolonged use than polyethylene.
Moisture sensitivity: This is the most significant practical limitation. Compostable bags will begin to break down when exposed to prolonged moisture or humidity, meaning they can become sticky, soften, or develop holes if left in a wet bin for too long. They are not a good choice for holding liquids or very wet waste over extended periods.
Shelf life: Because they are designed to biodegrade, compostable bags have a shorter shelf life than conventional plastic. They should be stored in cool, dry conditions and used within the manufacturer’s recommended timeframe.
Cost: Compostable bags are currently the most expensive of the three options, reflecting the higher cost of bio-based feedstocks and more complex manufacturing processes.
End-of-Life: Where Do They Actually Go?
This is the most important consideration with compostable bags. A compostable bag is only as good as the composting system it enters. There are three possible end-of-life paths:
Industrial composting is where certified compostable bags perform as designed. Under the high temperatures, typically above 55 degrees Celsius, and managed conditions of an industrial facility, certified compostable bags will break down completely within 12 weeks. Many Australian councils now operate green-waste and food organics collections processed through industrial composting, and in these programmes, certified compostable bags are often the preferred liner.
Home composting is suitable for bags certified to AS 5810, which can be added to a well-maintained home compost system, though breakdown will be slower than in an industrial setting.
Landfill is where reality diverges from the marketing. If a compostable bag ends up in general landfill, which most do, it may not break down significantly faster than conventional plastic. Modern landfills are designed to be stable containment systems, not biological processing environments. This is not a reason to avoid compostable bags altogether, but it is an important reality check on the assumption that “compostable” automatically means “better for the environment.”
Best Suited For
- Organics and food scrap collections where your local council requires or accepts certified compostable liners
- Home composting bins for kitchen scraps
- Businesses in the food and hospitality sector with organic waste streams diverted to composting facilities
- Households committed to diverting as much organic waste as possible from landfill
Comparing the Three: A Practical Summary
| Traditional Plastic | Biodegradable | Certified Compostable | |
| Material | LDPE / HDPE polyethylene | PE with additives or bio-blends | PLA, PBAT, starch blends |
| Strength | Excellent | Good to excellent | Moderate to good |
| Moisture resistance | Excellent | Good | Limited |
| Shelf life | Very long | Medium to long | Shorter |
| Cost | Low | Medium | Higher |
| Breaks down in landfill | No | Limited / partially | Minimal without proper conditions |
| Breaks down in composting | No | Varies by type | Yes, if certified |
| Best use case | General, industrial, wet waste | Light commercial, transition option | Organics diversion, home compost |
A Word on Marketing Claims
The packaging industry is not without its share of greenwashing. When evaluating garbage bags, keep the following in mind:
“Degradable” is not the same as “biodegradable.” Degradable bags often just fragment into smaller pieces of plastic rather than breaking down biologically.
“Biodegradable” without certification is a vague claim. Look for third-party certification marks from recognised bodies such as the ABA.
“Eco-friendly” and “green” are not defined terms. These marketing phrases carry no regulatory weight and tell you very little about actual environmental impact.
“Compostable” should come with a certification logo. In Australia, look for the ABA seedling logo and reference to AS 4736 (industrial) or AS 5810 (home composting). If a bag cannot point to a specific certification standard, it is worth asking more questions before accepting the environmental claim at face value.
Why Quality Manufacturing Matters
Regardless of the material type you choose, the quality of the manufacturing process has a significant bearing on how well your garbage bags actually perform. A bag made from substandard film, poorly sealed seams, or inconsistent thickness will fail in use regardless of what material it is made from.
At Plastpack, we manufacture our bags in-house at our Australian facility, controlling the film extrusion, printing, and bag-forming processes ourselves and maintaining tight tolerances at every step. We hold approximately 50 tonnes of film stock on hand, which means we can turn orders around quickly without compromising on quality. Whether you need standard household bin liners or heavy-duty industrial garbage bags in large volumes, our team has the experience and capability to deliver bags that perform exactly as required.
Frequently Asked Questions
1. What is the difference between biodegradable and compostable garbage bags?
Biodegradable is a broad term that simply means a material can break down through biological activity, but it gives no indication of how long that process takes or what conditions are required. Compostable is a more specific term, and when backed by certification such as the Australian Standard AS 4736, it means the bag has been independently verified to break down completely within a defined timeframe in a composting environment. Not all biodegradable bags are compostable, but all certified compostable bags are biodegradable.
2. Can I use compostable bags in my regular council green bin?
This depends entirely on your local council. Many councils that operate food organics and garden organics (FOGO) collection services do accept certified compostable liners, but policies vary between areas and may change over time. Always check directly with your council before using compostable bags in any kerbside collection service to make sure they are compatible with the processing facility used in your area.
3. How do I know what thickness garbage bag I need?
Thickness is measured in microns (µm) in Australia. As a general guide, lighter household waste works fine with a 15 to 20 micron bag, medium-weight general waste suits a 30 to 50 micron bag, and heavy or sharp waste such as construction debris or industrial materials requires 60 microns or above. If you are unsure, the Plastpack team can help you work out the right specification based on your application and typical bin load.
4. Are traditional plastic garbage bags recyclable?
Clean, dry polyethylene bags (LDPE) are technically recyclable, but they cannot go into your kerbside recycling bin because they jam sorting machinery. In Australia, soft plastics including garbage bags can be dropped off at participating collection points. Bags that have been in contact with food waste or other contaminants generally cannot be recycled, so it is worth checking the conditions of any scheme available in your area.
5. Do compostable bags really break down in landfill?
In most cases, no. Modern landfills are engineered to be stable containment environments, not active biological processors. They are typically low in oxygen and moisture, which are the very conditions compostable materials need in order to break down properly. As a result, certified compostable bags sent to landfill may take a similar amount of time to degrade as conventional plastic. The environmental benefit of compostable bags is most fully realised when they are used specifically for organic waste that enters an industrial or home composting system, not when they end up in general landfill.