Australia’s two biggest supermarket chains say they will take joint responsibility for the enormous stockpiles of soft plastic left after the collapse of a major recycling scheme.

The privately run REDcycle scheme – at the time, Australia’s largest soft plastics recycling program – collapsed in November, leaving thousands of tonnes of waste stashed in warehouses across Australia.

Since then, 32 stockpiles of plastic waste have been found in three states – 12,393 tonnes of rubbish consumers thought would have been turned into street furniture, fence posts and the like by now.

The latest four warehouses were identified earlier in February, and it’s possible more are yet to be discovered.

Coles and Woolies are now offering to take back the waste collected in their stores and work on a solution so it doesn’t “unnecessarily” end up in landfill.

Coles sustainability chief Matt Swindells said the two chains paid REDcycle more than $20 million in the last decade “to ensure [recycling] would happen”.

“We remain deeply disappointed by the unrecycled stockpiles,” he said.

REDcycle founder and CEO Liz Kasell has welcomed the “supportive and collaborative approach by Coles and Woolworths” and has indicated she will have more to say on the offer later.

Environment Minister Tanya Plibersek has welcomed the offer.

“Australians went to great effort to sort and take their plastics back to supermarkets to ensure they were recycled by REDcycle. I am determined to ensure that this effort was not in vain, and that they can be confident their plastics won’t go to landfill,” she said late on Thursday.

“Today’s announcement from Woolworths and Coles to responsibly manage the stockpiles is a big step forward. It will mean a lot to all the Australians who took the time to return their plastics for recycling – their efforts have not gone to waste.”

Ms Plibersek said the Soft Plastics Taskforce – which includes Coles, Woolworths and Aldi – would release a plan next week with information about how collection systems would be reinstated across Australia. She described Thursday’s announcement as “a really positive first step”.

Accepting the offer would mean stockpiled waste would no longer go straight to landfill. But it would not be an ultimate solution to recycling the products.

Thousands of tonnes of soft plastic are stashed in warehouses across the country.

The offer came just days before a legal bid by an aggrieved creditor to wind up RG Programs and Services Pty Ltd, the company behind the REDcycle scheme.

BTG Logistics claims it hasn’t been paid for storing 660 tonnes of plastic for REDcycle. The matter will be heard in a NSW court on Monday.

REDcycle has previously denied its stockpiling activities were a cover up, rather an attempt to ride out problems including a 350 per cent jump in the volume of returned plastics during the pandemic, the loss of its largest taker of returned plastics due to a fire, and a lack of processing capacity.

Coles and Woolies have said they did not know the waste they were collecting for the scheme was being stockpiled.

REDcycle’s parent company also faces charges brought by Victoria’s environmental watchdog, accusing it of failing to comply with a direction to reveal the locations of its stockpiles.

NSW’s environmental watchdog last month issued Coles and Woolies with a draft clean up notice for 5200 tonnes of plastic stored at 15 sites in that state.

It said the retailers had a responsibility to address the problem as participants in the REDcycle scheme, and generators of much of the waste it collected.

That notice was revised earlier this week after the watchdog said Coles and Woolworths appeared willing to cooperate and address immediate safety concerns.

The revised notice gives the retailers seven weeks to remove the stockpiles from their current locations and safely store them elsewhere, for up to a year.

“One of the interim options in the notice is to temporarily store the materials inside sealed shipping containers at a lawful facility,” the NSW Environment Protection Authority said in a statement on Thursday night.

“Beyond the interim storage measures, the revised notice gives the retailers 12 months to develop a lawful solution that determines the future of the materials, whether that be reprocessing at a recycling facility, exporting it overseas, or, as a last resort, sending it to landfill.”

Ms Kasell founded REDcycle in 2011, alarmed by the amount of soft plastic going into her kitchen bin. She is the sole shareholder of REDcycle’s parent company, RG Programs and Services.

She has previously declined requests for interviews and the operation has refused to answer questions about its financial position.

“As we are considered a very small business with under 50 employees, we are not required to publicly disclose financial statements,” a spokesperson said recently.

Coles and Woolies have made it clear their offer does not involve any assumption of past REDcycle liabilities, and is not an offer to acquire the REDcycle business.

-with AAP