The supermarket giants are among a raft of companies in Australia to sign up to the Plastic Pact, which sees them commit to making all their plastics recyclable, reusable or compostable by 2025.
Both supermarkets have faced the wrath of customers in recent years who question the supermarkets' commitment to greener alternatives, despite their claims of a significantly reduced plastic output.
Notably, Coles and Woolworths scrapped the single use plastic bag in 2018. Yet while they boasted of saving a combined total of 5.9 billion bags from landfill in its first year, questions were raised over the bags' replacements.
"The critical question there is what’s happened to the sale of other plastic bags?” University of Melbourne’s behaviour change and environmental sustainability expert Geoffrey Binder previously told Yahoo News Australia, saying he didn't believe less plastics were being used as a result of the change.
In wake of the latest announcement, both supermarkets hailed their ongoing commitments to sustainability.
"In recent years we've removed thousands of tonnes of plastic from our packaging and stores, but we know there's more to do, and we can't do it alone," Woolworths head of sustainability Adrian Cullen said.
Coles chief executive Greg Davis lauded the Pact as a step towards the company goal of becoming Australia's most sustainable supermarket, with zero waste.
Almost 60 businesses from across the Oceania region have committed to the pact, including Unilever, Coca-Cola, Nestle and Arnott's Biscuits.
Change needed across the chain, expert warns
Plastic producers and recyclers are also involved in the pact, a commitment Australian Packaging Covenant Organisation's Brooke Donnelly says is vital.
"Design is really important in terms of ensuring that you create packaging that has the best chance of making it through the system and being sorted and collected and recovered," she said.
Both supermarkets have drawn criticism over their soft plastics output, and while such packaging among fresh produce has been reduced, Coles and Woolworths place great emphasis on the REDcycle scheme which repurposes customers' soft plastics into new items such as tables and chairs.
Yet Dr Binder argues more is needed from supermarkets to educate their customers on plastic waste and ensure they “strategically modify their behaviours”.
Ms Donnelly says while some plastic producers need to eradicate certain plastics that are difficult to recycle, there are also issues in Australia's recycling infrastructure.
Victoria, for example, has been plagued by a recycling crisis in recent years, struggling to process contaminated recycling which led to warehouse-full quantities of unwanted materials.
"There's a bit of a speed hump period that we need to go through to get the right infrastructure to support higher levels of plastic recycling," she said.
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