Triple-zero received multiple calls from neighbours after the fire broke out on Dumfries Avenue at 1.30pm on Friday, March 22.

Fire and Rescue NSW assigned four fire trucks to the blaze, with the first crew arriving within minutes of emergency calls to find a single-storey house with smoke and flames billowing from the windows and roof.

"Initially it was unconfirmed if anyone was inside, so one crew wearing all their protective gear went in with a hose line and did a search and rescue," Duty Commander Illawarra Inspector Chad Wallace said.

"It was quickly determined there was no one in the dwelling so they concentrated their efforts on putting the fire out."

The fire - which was brought under control within 30 minutes - destroyed a bedroom and bathroom, with smoke and heat damaging the rest of the house.

"There were people living there but no-one was home at the time," Insp Wallace said.

It's understood neighbouring properties were also damaged by the flames.

Firefighters are now working with NSW Police to work out how the fire started, however initial reports did not suggest the fire was suspicious.