Police say the fire was lit between 5am and 6.30am but was extinguished using a hose.

They are now looking for a car that was seen in the area, described as an old red or maroon Mitsubishi Magna with a dark blue front-left panel.

"Police are seeking witnesses to the incident and information from anyone who may have either seen this vehicle in the area or know of such a vehicle," ACT Policing said in a statement.

Anyone with information can contact Crime Stoppers on 1800 333 000 or using their website.