Crews battle to protect properties as fires rage

Bureau of Meteorology senior meteorologist Michael Ephron said wind changes were always a concern with fire in the landscape, but the bureau would keep an eye on timings and positioning of those winds.

The biggest of the fires still burning, in the Grampians, was a "long way from over", Forest Fire Management Victoria chief fire officer Chris Hardman said.

He said while crews were fatigued, authorities were ensuring firefighters were being rotated. 

"This is a long game, and they're going to need to be maintain their capability and fitness to be able to do this for many more weeks to come," he told reporters.

"It's been a very long season, and we are still very much at the beginning of that season. We can expect this fire season to go through toward the end of February even into March."

Horsham Incident Control Centre Deputy Incident Controller Ben Matthews said more than 500 firefighters, aided by multiple aircraft, were working to contain the fires, with a focus on asset protection, particularly in the Victoria Valley.

He said strong winds had already caused numerous spot fires, but despite the dynamic and rapidly changing situation, firefighters from both Victoria and interstate were working tirelessly.

An emergency warning remains in place for the Grampians fire not yet under control.

Victorian fire crews are bracing for a wind change which will make conditions more challenging. (Diego Fedele/AAP PHOTOS)

Additional watch and act orders have been issued for four fires in the Great Otways National Park in Victoria's southwest, at Apollo Bay, Cape Horn, Hordern Vale and Cape Otway

Temperatures are set to peak at 42C in Ouyen, 35C in Melbourne and Ararat and 32C in Geelong. 

A cool change is due to move through South Australia on Tuesday afternoon before crossing into Victoria and Tasmania. 

It will then be Western Australia's turn for heatwave conditions later in the week.

All nine Victorian regions have high fire danger ratings on Tuesday.