Police are treating a fire that damaged the front door of a Christie Downs unit as suspicious.

Just before 2am on Saturday 1 May, police were called to a group of units on Hepburn Road, after reports a front door of a unit was on fire.

Fire crews were quick to respond and extinguished the fire before it could take hold and spread, with only minor damage caused to the door.

Police are treating the cause of the fire as suspicious. A police Crime Scene Examiner will attend the scene this morning to investigate.

There were no injuries with the occupier of the unit returning home shortly after the incident.

Anyone with information on the fire is asked to contact Crime Stoppers on 1800 333 000.