Police are investigating a deliberately lit fire at Aldinga early this morning.

Just before 5am on Monday 29 May police and MFS were called to Ratcliff Road after reports of a house on fire.

MFS quickly extinguished the blaze but the house was significantly damaged. The two occupants who were home at the time of the fire escaped without injury.

The fire has been deemed suspicious and Crime Scene Investigators will examine the scene today.

Anyone with any information is asked to contact Crime Stoppers on 1800 333 000 or online at www.crimestopperssa.com.au