Taylor Swift fans assured mulch issue won't stop shows

The reassurance came as minister Penny Sharpe blamed regulatory failures for distribution of potentially contaminated mulch that has forced school closures and testing at hundreds of sites.

Ms Sharpe assured fans that Taylor Swift's shows would go ahead next week at Accor Stadium at Sydney Olympic Park, with initial tests of mulch from there not detecting asbestos.

"This will not stop Taylor Swift performing in Sydney," she told the ABC.

"We are testing samples but, regardless, we can remove the mulch and remediate before Taylor Swift takes to the stage in the Harbour City."

A spokesperson for the NSW Environment Protection Authority said in a statement the Sydney Olympic Park Authority was inspecting mulch that came through the same supplier identified at other Sydney sites.

"At this stage, there is no sign of any asbestos in the mulch around the park."

Urgent testing of garden mulch is under way at seven Sydney schools as the state's asbestos-tainted mulch scandal widens.

"There's clearly a regulatory failure here ... these products should not be in this mulch," Ms Sharpe told reporters on Friday.

"We will look at increased penalties, we'll look at a different regulation regime if we need to to make sure that this doesn't happen again."

Ms Sharpe's comments come as environmental inspectors test mulch at primary and high school campuses that originated with manufacturer Greenlife Resource Recovery.

A supermarket and a second hospital were added to the growing list of NSW sites found with asbestos-tainted recycled mulch, all linked to Greenlife.

"This investigation is around this one supplier that's been found to have contaminated products in 10 per cent of where it's been distributed," Ms Sharpe said.

Some residential properties are also due to be tested after receiving the product from landscapers.

A major investigation continues into how pieces of bonded asbestos, mostly about the size of a coin, ended up in the commercially-sold mulch.

One piece found at Harmony Park in inner Sydney was small enough to fit up someone's nose and therefore categorised as friable asbestos, a more dangerous substance.

But NSW Health's message to parents was that the risk to human health remained low if asbestos was bonded and not disturbed.

"It's important to remember that asbestos primarily causes illness when little fibres that are very small, are breathed in," senior health official Jeremy McAnulty said on Friday.

"The risk is higher, the more you breathe in over longer periods of time."

The seven schools subject to testing range from public to private and primary to secondary, and follow the closure of Liverpool West Public School on Monday due to a positive result.

The decision to keep most schools open during the testing was defended by NSW Education Department secretary Murat Dizdar.

"Liverpool West was a clear-cut decision - that mulch was right across the school, very close to buildings - whereas at Allambie Heights it was two trees, a garden bed, easy to cordoned-off," he told reporters.

Greenlife is the common thread between all positive detections across Sydney and Nowra, although the company denies its product was contaminated under its watch.

"Greenlife is confident mulch leaving our facility is free of asbestos contamination," it said in a statement on Friday, adding recycled mulch is independently tested by a laboratory approved by National Authorities Testing Australia.

The company is challenging a NSW Environment Protection Authority prevention order in court, saying its testing has shown mulch stockpiled at its facility was free of asbestos contamination.

A multi-agency task force was set up on Thursday night to deal with the unfolding crisis potentially affecting hundreds of sites across the state.

It includes representatives from the NSW Asbestos Coordination Committee, Safework NSW, Local Government NSW as well as fire, health and education officials.

Since bonded asbestos was first found at the Rozelle Parklands in Sydney's inner west in early January, the criminal investigation has grown into the largest in the EPA's history.

The number of positive sites grew to at least 25 on Friday as positive results were reported at St John of God Richmond Hospital, Woolworths at Kellyville and a Transport for NSW park in Wiley Park.

Already, 200 sites have been tested with hundreds more expected to require inspection.

One difficulty facing authorities is Greenlife distributed its recycled mulch product to 30 companies, some of whom passed it further down the chain.

Australian Associated Press