Rozelle Parklands was ground zero for the contamination scandal, after mulch containing fragments of bonded asbestos was detected in January.

Further tests confirmed contaminated mulch had been used at a number of schools, hospitals and other parks in Sydney and surrounds throughout February, while similar issues had also been picked up in the ACT and Queensland.

The number of positive sites in NSW had risen to 61 on Saturday after hundreds of tests around the state.

Rozelle Parklands, in Sydney’s inner west, was closed to remove the mulch less than a month after it opened on the site of former rail yards atop a massive underground motorway interchange.

But the original deadline, expiring at 5pm today (Thursday), has been extended by four weeks to March 28.

Transport for NSW requested an extension last Friday after the original notice from the Environmental Protection Authority (EPA) was expanded to include some surrounding areas.

“The EPA has also acknowledged the ongoing difficulties of the clean-up, including challenges related to removing mulch adjacent to the road corridor,” the transport department said in a statement on Thursday.

“These sites require overnight road-occupancy licences, involving traffic management set-up, the establishment of a protected work-zone and decommissioning the same night.”

Some areas require further risk assessment and control measures to manage the environmental and human health risks associated with the removal of mulch, the EPA’s varied clean-up notice issued on Wednesday noted.

Once the mulch has been removed by departmental staff, working with Rozelle contractors John Holland-CPB, a licensed asbestos assessor would certify the contamination had been cleared, Transport for NSW said.

Inner West Council issued asbestos clean-up notices to the contractors on Monday after it became obvious the deadline would not be met.

“It seems that because the EPA clean-up notice was issued to Transport for NSW, these contractors have decided that they aren’t accountable for adhering to the deadline,” Mayor Darcy Byrne said.

The delay has outraged the community, Balmain Greens MP Kobi Shetty said.

“It is incredibly frustrating news after we have waited so long for this park to be opened – to then have it open for less than a month before it was shut down,” she said.

The Sydney outbreak sparked inspections in southeast Queensland, with asbestos detected in a compost stockpile at company NuGrow’s Ipswich site west of Brisbane.

About 25 sites received mulch from NuGrow that might contain the hazardous material.

It has been revealed a dog park is among the sites being investigated.

A southeast Queensland independent school had already been identified as one of the sites.

Health Minister Shannon Fentiman said 15 businesses have been identified.

NuGrow is the only site to to return a positive result after 23 southeast Queensland sites were inspected.

Results from half of the tested sites will be returned by Friday.