A Victoria Police forensics unit will search a badly burnt house in Cardigan this afternoon to determine the blaze's cause.
CFA operations officer Malcolm Bruce said fire units were called to the Whites Road home just after 4am but it was already well alight.
He said the roof of the single storey, brick veneer home had partially caved in and the house had been badly damaged by the fire.
No-one was home at the time of the blaze but Mr Bruce said the owner returned this morning to find his house virtually gutted.
CFA fire investigators were also on scene this morning.
Units from Ballarat City, Wendouree, Cardigan and Burrumbeet all attended the fire, which took about 30 minutes to bring under control.