State Police Commissioner Christine Nixon says all the bush fires in Victoria will be treated as crime scenes to determine if arson was involved.
The death toll in the bushfires is now 108 and the number is expected to rise.
Ms Nixon told the Seven Network on Monday forensic investigators have already begun work in the Churchill region, where arson is suspected.
Forensic investigators have also begun work in the Kinglake area.
Ms Nixon told ABC Radio that" wherever a death has occurred we investigate that as a crime."
As at 530am (AEDT) on Monday, 31 fires were still burning across the state. Some fires could take weeks to contain.
The Country Fire Authority and the Department of Sustainability & Environment said at least 750 houses have been destroyed and more than 330,000 hectares burned.
The weekend death toll surpasses that from the 1983 Ash Wednesday bushfires, in which 75 people died in Victoria and South Australia, and the Black Friday bushfires of 1939, which killed 71.
Two charged in NSW
Two people have been charged with starting bushfires over the weekend in New South Wales.
The ABC reports a man, 31, has been charged with starting a large bushfire that's burned 200 hectares at Peats Ridge, on the Central Plateau.
A boy, 15, has also been charged with letting off an explosive that caused a small bushfire in the Blue Mountains, Sundday.
Rural Fire Service Commissioner Shane Fitzsimons says a small strike force is investigating all fires vigilantly.
