Australian supermarkets have been accused of secrecy and relying on "false solutions" while claiming they are tackling the plastic packaging crisis.
An audit has handed Australia's four largest grocery retailers a fail grade for their efforts to deal with the mountain of plastic that encases the products on their shelves.
Aldi was the best of a bad bunch, scoring 20 per cent for its efforts, ahead of Coles on 15, Woolworths on 10, and Metcash - which owns the IGA/Foodland brands - on just 3 per cent.
The audit, by the Australian Marine Conservation Society and the Boomerang Alliance, is a first attempt to independently verify what grocery retailers are doing to address the problem.
The overwhelming conclusion is not nearly enough.
"Unwillingness to publicly release packaging data amongst most supermarkets indicates that the use of plastics may not be reducing in real terms," it says.
"All four supermarkets were unable to demonstrate evidence of significant progress in resource recovery and increasing the use of recycled plastic content."
When supermarkets did release data, it was cherry-picked, the audit says.
"Supermarkets are only applying plastic reduction targets to own-brand products.
"By only measuring and reporting against targets for their own-brand packaging, Woolworths, Coles and Metcash avoid taking responsibility for the majority of plastics on their shelves.
"Without the whole picture, Australian consumers cannot have confidence that supermarkets have reduced plastic in any meaningful manner."
The audit was based on data provided by supermarkets, in public reports, and on shopper surveys. The bulk of each score was based on actions to reduce, reuse and recycle plastic.
AMCS plastics campaign manager Shane Cucow co-authored the report and said the audit exposed some worrying practices.
One is light-weighting, where the thickness of plastic packaging is reduced rather than replaced with something better.
While there are benefits, Mr Cucow says it perpetuates plastic use and supermarkets can avoid more effective solutions like providing reuse and refill options.
There is also evidence supermarkets are pivoting towards soft plastics, which are harder to recycle.
Australia has never had a soft plastics scheme capable of recycling the volume produced, even before the small REDcycle program collapsed.
While supermarkets are part of efforts to establish a new scheme, Mr Cucow says it will be years before that's operating at scale.
All of that adds up to a concerning situation where transparency is lacking, solutions can be dubious, retailers are reporting on progress in whatever way they like, and customers can't be sure of outcomes, he says.
"What we're seeing in the annual report of companies like Woolworths, for example, is they're reporting that they've reduced virgin plastics. But they don't show how that was done. And underneath that, what we see is things like lightweighting, or moving to things like soft plastics."
Mr Cucow says supermarkets must also explain why plastic-wrapped fruit and vegetables were cheaper than loose produce 78 per cent of the time.
Woolworths says it is "disappointing to see that this report has based its ratings on incomplete data, and as a result is not a reliable reflection of packaging sustainability at Woolworths".
"We've removed more than 1.4 million kilograms of virgin plastic from our range since 2018, and across all the packaging we can control there is an average recycled content of 49 per cent."
"We know there is still more to do, and we will continue to publish our packaging data to hold ourselves accountable for our progress, while encouraging our suppliers to do the same."
Coles says 83.8 per cent of Coles Own Brand packaging is recyclable, and recent improvements include reducing plastic packaging on some Own Brand products, and switching to paper shopping bags - replacing the 230 million soft plastic bags it used to sell annually.
Aldi says it reports transparently on its commitments, which include reducing plastic packaging by 25 per cent by 2025, with 83 per cent of its packaging currently recyclable, reusable or compostable.
Metcash said it would review the report and look to make improvements while continuing to work with stores.