Queanbeyan police are treating the Kinsella Street property as a crime scene as they investigate what sparked the blaze.

Duty officer Chris Varley said the fire started just after 5pm.

He said the home owners were overseas and no one was injured.

"It was a major fire - the home is virtually destroyed," he said.

"It's not good time of year for something like this to happen. It was a good thing no one was hurt."

Radiant heat caused minor damage to a house next door, including a broken window and damage to some items just outside the house.

A car on the neighbour's property was also damaged.

Both NSW and ACT firefighters brought the fire under control.

Queanbeyan Police Sergeant Ben Bowles said fire damage to the property was estimated to exceed $500,000 and his teams were preparing a report for the Queanbeyan Local Court.

The site investigation was concluded on at 2pm on Saturday, December 20.