A fast-moving blaze that threatened more than 100 homes during extreme fire conditions in Victoria’s west is being treated as suspicious.

The fire at Dereel, about 30km south of Ballarat, and another at Bayindeen west of Ballarat have been contained after an intense firefight.

The cause of the Dereel blaze is under investigation because there was no dry lightening in the area, Emergency Management Commissioner Rick Nugent said.

“We don’t believe there was any tractors or other machinery working in that area at the time,” Nugent told reporters in Ballarat on Thursday.

“So at the moment we are treating that fire as suspicious until we are able to prove differently.”

Flames were whipped up by strong hot winds during catastrophic fire conditions on Wednesday, prompting a warning for residents to shelter indoors.

Nugent said at least one out building had been lost and firefighters saved 117 homes at Dereel.

“What I’ve heard from the firefighting crew is they were putting the fire out on the doorstep (of homes), on back pergolas, in back yards, in front yards,” he said.

Victorian Premier Jacinta Allan it was “unfathomable” that someone would create so much work and heartache for thousands of people.

Flames came within kilometres of Michelle de Groot’s house in Dereel.

She said she sought shelter at two evacuation centres, which had to be evacuated as the fire grew.

“We were choking on smoke, everyone’s there yelling ‘get out, you have to leave, it’s not safe’,” de Groot told ABC radio.

Her husband stayed to defend a local property and said the fire was so loud he could not hear water-bombing aircraft as they passed over the area.

“He said it was so quick, it was really quick and hot and the noise was horrendous, it was pretty hairy,” she said.

Hundreds of firefighters battled the Bayindeen-Rocky Road blaze west of Ballarat and stopped it from spreading by building containment lines around its 157km perimeter.

Watch and act alerts remain in place for both fires as authorities warn it is still not safe for anyone to return to Dereel, Amphitheatre, Bayindeen, Ben Nevis, Chute, Elmhurst, Eversley, Glenlogie, Mount Cole, Mount Lonarch and Raglan.

“There’s still work to be done to make sure that there’s no hazards near the area, particularly after these types of fires we need to check the trees haven’t been damaged by fire and are going to fall,” State Control Centre spokesman Luke Hegarty told AAP.

Some 30,000 people in communities near the Bayindeen blaze were warned earlier in the week their towns could be at risk and they should consider leaving the area.

Many left by Wednesday and those who do not live in towns covered by the emergency warning can now return.

“The lower numbers of properties that we’ve seen damaged, the fact that there has not been, in the case of the fires, a loss of life I think speaks directly to the fact that Victorians have heeded the warnings,” Premier Jacinta Allan said.

Hundreds of firefighters will keep working to control the Bayindeen-Rocky Road fire, which has burned through 22,000 hectares, before conditions are expected to spike again next Wednesday.

Lower temperatures were expected on Thursday following a cool change after Mildura on Wednesday reached the mid-40Cs.

As of Thursday morning, six homes, and sheep and cattle stock were lost to the Bayindeen blaze.

Farmers impacted by bushfires and storms since February 9 can now apply for grants of up to $5000 from the Victorian Farmers Federation.

“Farmers have lost farm sheds, kilometres of fencing, stock, machinery and that’s just from early assessments,” president Emma Germano said.

Wildlife Victoria is expecting an influx of injured animals so the organisation has extra people working in phone rooms to make sure all cases are attended to.

Members of the public are urged to phone Wildlife Victoria for help if they spot an injured animal.

-AAP