Firefighters have extinguished a car fire in Watson overnight.

At about 9pm, ACT Fire and Rescue responded to reports of a car fire on Antill Street.

The car was located well alight next to grass lands with firefighters extinguishing the vehicle and grass a short time later.

The cause of the fire is suspicious, and the incident has been handed to ACT Policing.

Anyone who witnessed persons leaving the scene shortly before the fire is urged to contact Crimestoppers on 1800 333 000.