POLICE are warning of a possible repeat of Victoria's Black Saturday bushfires, launching a crackdown on arsonists in NSW.
More than 3000 bush and grass fires have been recorded across NSW so far this spring, with 37 burning yesterday - including a significant blaze near Lake Macquarie.
With temperatures rising into the 30s this week, coupled with strong westerly winds, NSW Police announced it was restarting Strike Force Tronto (Tronto) to target would-be firebugs.
"I'd like the public to understand that the people who light fires put everybody at risk," Detective Acting Superintendent Ian McNab said.
"There's a huge risk in even just a small grass fire.
"A small grass fire can turn into something catastrophic as we saw in Victoria back in 2009."
In 2009 the Black Saturday bushfires killed 173 people and destroyed more than 2000 homes.
Rural Fire Service (RFS) deputy commissioner Rob Rogers said about 350 bushfires were investigated every year in NSW and about 100 of those were deliberately lit.
A significant number of fires so far this spring have already been identified as the work of arsonists, including several blazes around St Marys, in Sydney's west, last night.
Those fires, which had numerous ignition points, were brought under control about 8pm (AEDT) and Det Sup McNab said police already have intelligence about the perpetrators and arrests expected in coming days.
The 37 bush and grass fires burning today were mostly in the state's north, Mr Rogers said.
The RFS issued a watch and act notice for the Lake Macquarie fire, near Racecourse Road at Teralba, which had destroyed 40ha by 3pm (AEDT).
Mr Rogers said the blaze shouldn't pose a danger to homes, but more would be known by 6pm (AEDT).
While it is unclear how that fire started, authorities have not ruled out arson.