Three more suburban parks have been caught up in an asbestos scare, which has now spread to 10 sites across Melbourne in three separate council areas.

The Environment Protection Authority is investigating after the cancer-causing substance was found at parks within Hobsons Bay and Merri-bek councils.

On Tuesday, the authority revealed it had received new reports of material likely to contain traces of asbestos in three other parks.

They are garden beds near a bowls club at Dennis Reserve in Williamstown, Altona Coastal Park and Fitzgerald Square Reserve in Sunshine West, which is part of Brimbank City Council.

The authority says it is continuing to investigate sources of material and it has received queries related to residential properties, however, public areas are its priority.

It’s also working with Hobsons Bay City Council on potential sources of mulch, which it said may have been delivered to parks at Altona North as far back as 2017.

Inspectors previously confirmed asbestos was found at the under-construction park at Hosken Reserve at North Coburg, the PJ Lynch Reserve at Altona North and the Donald McLean Reserve at Spotswood.

Lab results on Tuesday afternoon are expected to confirm contamination results at PA Burns Reserve at Altona, GJ Hosken Reserve at Altona North, Crofts Reserve at Altona North and Shore Reserve at Pascoe Vale South.

Early investigations raised concerns the asbestos was being introduced to the parks through mulch deliveries, like the contaminated mulch crisis in NSW.

But the regulator has previously said there was no evidence of that.

“Mulch producers are unlikely the source for this contamination,” the authority’s Duncan Pendrigh told reporters on Monday.

“There may be something being introduced in the supply chain.”

The pieces of confirmed asbestos found at the Melbourne parks so far have been bonded asbestos, rather than the more dangerous friable asbestos.

Bonded asbestos is considered low-risk for people who come into contact with it, unless fibres are released into the air because of damage or bad weather, the regulator said.

It comes as a pile of burning rubbish suspected of being contaminated with asbestos was found on a roadside at Rossmore in outer Sydney.

It was found about 15 minutes away from tips that accept asbestos.

The material has been found in recycled mulch at some 70 sites in Sydney this year, prompting schools and parks to close.

– AAP