Emergency services were called to a home in Villawood overnight following reports of a fire inside.
About 12.40am, police were called to the Binna Burra Street home where they found a fire burning inside a bedroom of the unoccupied home.
The fire was extinguished and a full investigation into the cause of it is now underway.
Police are treating the fire as suspicious.
Anyone with information about this incident should call Crime Stoppers on 1800 333 000.