Residents returning home after the NSW bushfires have been warned that asbestos has been found in at least 48 of the properties so far inspected.
About 235 homes have been assessed and 175 analysed further for asbestos, with the dangerous material detected in 48 houses, former NSW Rural Fire Service commissioner Phil Koperberg told ABC radio on Friday.
"Any house built prior to 1987 is more likely than not to have an asbestos content," he said.
Many areas are yet to be inspected and even though the risk of exposure is "low," Mr Koperberg warned people to stay out of their homes if they're unsure.
"(It's) better to be sure than sorry," he said.
Signs will be placed outside properties where asbestos is found and an information hotline will also be set up.
Mr Koperberg, who is the Blue Mountains emergency recovery co-ordinator, will visit Winmalee with Premier Barry O'Farrell on Friday.
Premier Barry O'Farrell said the asbestos risk was probably minimal.
"However it's better to be safe than sorry," he told reporters at the Winmalee Fire Station on Friday.
A co-ordinated clean up effort would be undertaken quickly, he said, and burnt out properties with asbestos would be sign-posted.
Blue Mountains Emergency Recovery co-ordinator Phil Koperberg said people who had already returned to homes shouldn't panic.
"This is an exponential type of event so the longer and the greater the exposure the higher the risk," he said.
"We're asking people who have been (to burnt out homes) not to go back until we've settled the sites down."
He said of the 235 homes destroyed by fire 67 had so far been found to have asbestos.
There were also safety concerns about arsenic in treated pine and of the potential for remaining structures to collapse.
Mr Koperberg said the asbestos assessment teams hadn't been able to get into the fire zones until Tuesday because conditions had been too dangerous.