Soft plastics that should have been recycled have been found stored at four more warehouses in Melbourne's western and northern suburbs.
Victoria's Environment Protection Authority located the new sites as part of its investigation into the collapsed REDcycle program.
The program was paused in November after it was revealed millions of plastic bags were stored in warehouses instead of being recycled.
Thousands of tonnes of soft plastic have been discovered at 14 sites across the city, including the four new locations in Laverton, Truganina, Tullamarine and Craigieburn.
EPA officers have already issued an improvement notice on the Truganina site, demanding better emergency access and a reduction in the stockpile.
The Laverton site was inspected on Thursday, with officers considering it to be a high risk due to concerns about the mix of materials.
The Tullamarine and Craigieburn sites are considered low risk.
There are currently seven warehouses that have regulatory notices issued to them over fire risk concerns.
"Our officers are determined to keep the community and environment safe," EPA chief executive Lee Miezis said.
"We are following up all new leads to find these sites."
In December, the EPA charged the REDcycle operators - RG Programs and Services - with offences under the Environment Protection Act.
The matter is due to go before the Sunshine Magistrates Court later this month.
