Firefighters were called to an automotive business on Tarnard Drive in Braeside around 4am after a car ploughed into the shop and was set on fire, police said.
Eight firetrucks arrived on the scene and it took more than a hour for firefighters to control the blaze, which caused significant damage to the building.
Crews were able to stop the flames from spreading to neighbouring businesses.
The blaze is now under control, however crews remain on the scene putting out hotspots.
Police said the offenders who set the car on fire fled the scene.
A crime scene has been established and an arson chemist is set to attend later today.
Anyone with information or footage of the incident is urged to contact police or Crime Stoppers on 1800 333 000.
