The residents of a house severely damaged by fire in Sydney's southwest have all been accounted for.
The Bass Hill home was well alight on Tuesday morning when four fire trucks arrived to put it out, dousing the flames within an hour, firefighters say.
Footage of the incident broadcast by the Nine Network shows bright orange flames and thick grey smoke billowing through large holes in the roof, with multiple charred beams visible.
Fire & Rescue superintendent Norman Buckley told AAP about half of the home was severely damaged.
"No people have been found inside the premises so that's a great thing, and no injuries to firefighters," he said.
"It has all been extinguished and confined to that house of origin."
Supt Buckley said the cause of the blaze is undetermined and an investigation unit will scour the property.
AAP understands a resident has since returned to the home and is assisting emergency services.