About 40,000 hectares have been destroyed in fires at Garvoc, Terang, Hawkesdale and Camperdown, which were fanned by winds of up to 104km/h. 

Deputy Premier James Merlino told a briefing on Sunday afternoon that sheds and machinery were also lost in the blazes.

He said 280 firefighters and 29 aircraft had been deployed across the state after the fires broke out on Saturday night.

The State Emergency Service received more than 400 requests for help and about 800 people reported to the five south-west relief centres for assistance or information.

Mr Merlino said lightning strikes were the primary cause of most of the fires but investigators were on the ground to confirm.

He said personal hardship payments of $1500 were being made available.

Many roads were closed on Sunday, including parts of the Great Ocean Road and the Princes Highway. 

Emergency Management Commissioner Craig Lapsley said not all of the homes destroyed were occupied, and there had been no deaths or major injuries reported.

Authorities issued 51 emergency warnings –  the highest level of warnings –  and 29 advice messages.

"I think the community has responded exceptionally well," Mr Lapsley said. "(There have been) no significant injuries, no death. I would say they have done exceptionally well."

Firefighters and the communities faced a number of challenges because the fires started at night.

"The challenges is you can't get fire trucks into some areas in the darkness; we are unable to fly aircraft, and that means our suppression activity is suppressed somewhat," Mr Lapsley said. 

"The community's done really well to look after themselves. But there has been significant losses. We've lost homes, farm machinery and sheds, and that's a huge impact on the community."

​Wannon MP Dan Tehan said the federal government would activate natural disaster relief arrangements if the state government asked for it. He had spoken with the Defence Minister, Chief of Army and Deputy Prime Minister and said the army was on standby to supply generators for dairy farmers and larger generators for electricity supplies, should the state request the assistance. ​