'I'd prefer action': Premier defends asbestos response

NSW Premier Chris Minns will not support a special inquiry into the state's waste management industry as investigators work to trace the sale of asbestos-contaminated mulch.

A total of 47 sites have been confirmed impacted while 798 tests have come back negative since bonded asbestos was detected in recycled mulch at the Rozelle Parklands in Sydney's inner west in January.

Sydney's asbestos-mulch issue has also spread to Canberra with the potentially contaminated product sold for 11 months in the capital.

Questioned on the growing crisis during a budget estimates hearing, Mr Minns said he would not support the establishment of a special inquiry into the state's waste industry.

"I'd prefer action rather than an inquiry," he said on Wednesday.

"I think that the best course of action is ... to be exploring enhanced penalties to ensure that those who break the law are investigated or punished, that the EPA (Environmental Protection Authority) has the resources in place and that the public has confidence in the market."

Macquarie Hospital in the city's north, Tresillian Family Care Centre at Wollstonecraft and Manly Adolescent and Young Adult Hospice are awaiting results from precautionary tests.

Samples taken from Mount Annan Christian College at Currans Hill and Trinity Catholic Primary School at Kemps Creek in southwest Sydney have returned negative results.

There are five schools affected, with one taking the decision to close for the week and another shut while students learn at a nearby site.

Two other schools at Oran Park in Sydney's west are awaiting results of precautionary tests after mulch donated by a developer to the nearby St Mary MacKillop Catholic Parish was found to contain asbestos.

The premier also defended the establishment of an expert taskforce to assist the NSW EPA with identifying the spread of the contaminated mulch.

He said a multi-agency response was appropriate given the scale of the issue.

"(The EPA) were making progress in identifying the sites, but there were three, perhaps even more, sub-contractors that had the quantum of mulch and then sold it on to third parties," he said.

"As a result of that, it was a complex contact-tracing endeavour and it wasn't an easy thing (for one agency) to do."

The majority of the mulch the EPA was concerned about has now been tracked down and tested, chief executive Tony Chappel confirmed on Tuesday.

"There are a number of other cash-sale type scenarios that we are just working through now, but it's a handful of private residences that have been impacted," he said.