POLICE are investigating whether a fire that razed a house near Pottsville was deliberately lit.

Firefighters in breathing apparatus battled the blaze for five hours, but the house collapsed in on itself and was completely destroyed.

Rural Fire Service duty officer Keith Moss said the house, located on the corner of Cudgera Creek and Pottsville roads, was well alight when they arrived just before 8pm on Thursday.

“Four Rural Fire Service trucks attended, as well as police and a Fire and Rescue NSW truck,” Mr Moss said.

“The house was totally destroyed by fire.

“Our last truck left about 1am.”

Mr Moss said the house continued to smoulder throughout the night.

“It rained overnight but it wasn't enough to put it out,” he said.

“An RFS truck returned this morning to dampen it down again.”

A New South Wales Police spokeswoman said emergency workers were alerted to the blaze by passing motorists.

“All the information we have is that the house was vacant,” the spokeswoman said.

“No one is believed to be injured.”

The spokeswoman said detectives attended the scene yesterday.

“It's standard procedure to treat all fires as suspicious until proven otherwise,” she said.

“We're unsure whether it was deliberately lit or not.

“The area is being preserved as a crime scene.”

A report is being prepared for the coroner.