Local councils are picking up more cardboard boxes for recycling but what's left inside many of them is still a big problem: pizza scraps.
"We still see pizza boxes with uneaten pizza still inside," the Australian Council of Recycling's interim chief executive Cameron O'Reilly told AAP.
"That was a clear pattern of behaviour during COVID."
While cardboard waste in kerbside recycling has increased about 10 per cent, pizza scraps and other food contamination can mean loads of carefully sorted recyclables have to be sent to landfill.
"Consumer behaviour makes a big difference to the level of recycling that occurs ... the issue is ensuring the quality is kept as high as possible," Mr O'Reilly said.
He says it's too early to know if there's more cardboard due to packaging from the boom in online deliveries or whether it's due to a shift away from plastics.
Australia generated about 74 million tonnes of waste in 2018-19, equal to just under three tonnes per person.
While more than 60 per cent of paper and cardboard waste is recycled, only 15 per cent of plastic is.
The rest ends up as landfill, litter or in the ocean.
The Australian Council of Recycling says it's crucial for governments and major companies to use their purchasing power to create demand for products made from recycled materials - otherwise recycling just produces processed waste.
And there are some promising signs.
In April, the Victorian government installed noise walls made from 75 per cent recycled plastic along the new Mordialloc Freeway - using 570 tonnes of plastic waste.
The state government's infrastructure projects require bidders to use as much reused and recycled content as possible.
Meanwhile the Municipal Association of Victoria says some councils are auditing people's recycling bins to see if individual households are contaminating whole loads of recycleable waste.
Only 10 local councils in Australia have kerbside collections that can accept all types of plastic, including plastic bags.
Recycling services are not available to most communities in remote and regional Australia.
Australian Associated Press