Several towns have been told to leave as temperatures soared to almost 50C in some areas.

Homes have been destroyed and fresh evacuate immediately orders issued for dozens of small towns near a large bushfire during severe heatwave conditions.

The bushfire at Carlisle River in the Otways Ranges, in southwest Victoria, is causing serious concern, after breaching containment lines.

The state is sweltering through its worst heatwave since 2009, with temperatures soaring above 40C, potentially smashing records.

At least three homes have been lost in the raging Otways fire, although it’s not clear if they are primary places of residence or holiday homes.

Authorities expect a strong “punchy” south-southwesterly wind change on Tuesday afternoon, which will create an erratic and extreme conditions in the Otways.

Wind gusts of up to 70 km/h are forecast for the region from 5pm.

“That fire will run. It will develop a plume and it will pick up really significant energy,” Forest Fire Management Victoria chief fire officer Chris Hardman said.

Firefighters fear a forecast wind change will create erratic and extreme conditions. (HANDOUT/Rockbank Fire Brigade) Credit: AAP

“The heat conditions are making things incredibly difficult for firefighters in Victoria.”

Townships of Barongarook, Gellibrand, Kawarren and Lovat have been added to the evacuation warnings.

“If you are located in these areas it is recommended you evacuate immediately and move to a safer location away from the fire,” the order said.

Another emergency warning has been issued for a fire near Camperdown in the state’s southwest.

It’s too late to leave for residents in Kariah, Larralea, Leslie Manor, Lismore, Taaraak.

Residents in the Greater Otways area have been urged to evacuate over fears about the growing Carlisle River fire. Credit: AAP

Electricity distributor Powercor says its emergency response plan has been activated, with crews monitoring impacts from the fires.

The Carlisle River fire is threatening two major distribution powerlines that supply the region.

“If bushfires damage or destroy parts of the power network, this will affect power supply to properties and impact equipment that relies on electricity such as electric water pumps,” network emergency manager Ben Hallet said.

Powercor is working with firefighters to dump fire retardant over large areas of powerlines in the region, while also sending a back-up generator to the coastal town of Apollo Bay.

There are a several watch and act warnings in place for the Walwa fire, near the NSW border, which has been burning for weeks.

A total fire ban remains current for Victoria on Tuesday, and has been declared for the Wimmera and North East districts on Wednesday.

“Tomorrow’s conditions will make it difficult to suppress new fire starts, as well as providing a challenge for firefighters already working hard on containing existing fires,” CFA chief officer Jason Heffernan said.

A community fire refuge is located at Otway CFA Fire Station as a last resort option for residents, although there’s no guarantee the route there will be safe.

Relief centres are open at multiple locations in the region, including Colac Showgrounds, Colac Blue Water Leisure Centre and Grovedale Community Hub.