Authorities have confirmed 34 homes have been lost in bushfires since Sunday. That is up from the earlier figure of 21.

In the meantime firefighters are hoping to take advantage of easing conditions today to get the upper hand on a large bushfire raging on Melbourne's northern fringe.

At least 19 blazes are burning out of control in Victoria, and fire crews are are focusing efforts on the Mickleham Road blaze.

Emergency warnings remain in place for the fire, which has already burnt through more than 20,000 hectares and destroyed at least 15 homes.

Spotfires are breaking out ahead of the blaze, which is travelling north from Wallan towards Bylands and Kilmore.

Authorities are particularly concerned about the eastern flank of the fire to the south of Kilmore.

Fire Services commissioner Craig Lapsley says the blaze has split and there are now two fire fronts.

"It's moved both east and west and it's certainly got significant pressure on Wallan and Kilmore. This is a fire of significance," he said.

Deputy incident controller John Leben says firefighters will be making the most of favourable conditions today ahead of warmer weather later this week.

Fire facts Trucks at Kilmore/Mickelham Rd fire: 200

Trucks at Kilmore/Mickelham Rd fire: 200 Aircraft deployed: 70

Aircraft deployed: 70 Area burnt: 20,000 hectares

Area burnt: 20,000 hectares Houses lost confirmed: 21

Houses lost confirmed: 21 Unconfirmed houses lost: dozens more

Unconfirmed houses lost: dozens more Firefighters from: Victoria, New South Wales, New Zealand

"While we've got this more benign weather, we're going to get in and do as much of the blacking out as possible prior to the increasing temperatures as the week goes on," he said.

Fires are also burning in other regions, including in the Gippsland and the far east.

All emergency warnings in those areas have been downgraded to watch and act status.

Assessment teams are on the ground today, including veterinarians to look after injured livestock.

Across the state, 21 homes have been confirmed lost, but James Todd from the state control centre says the number will grow.

"There are a further 20 unconfirmed reports of house losses and some of those relate to other parts of the state around the Latrobe Valley and perhaps East Gippsland," he said.

As well as the Mickleham Road fire, crews are particularly concerned about a blaze at the Hazelwood coal mine, near Morwell in the Latrobe Valley.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 3 minutes 52 seconds 3 m 52 s 12 fires believed to be deliberately lit

Fire crews are working to stop the fire from spreading to other areas where it may affect electricity generation.

Deputy Premier Peter Ryan says the blaze could burn for weeks.

"The real challenge in relation to the state's power supplies is to stop the fire getting into the other end of the pit where the productive work is done in terms of coal supply," he said on Monday.

"A lot of effort is going into achieving that, and at the moment the situation is holding."

Power has been restored to the giant coal dredgers and conveyor belts feeding the generators at the plant which were shut down after they were damaged by fire.

Falling trees hamper fight against fires

A large tree branch fell onto a truck at the Kilmore fire, cracking the windscreen. ( ABC News )

The fight has been hampered by falling trees in some areas.

A large tree branch fell onto a truck being used to fight the fire north of Melbourne overnight, cracking the windscreen.

Lieutenant Tony Tynan says the trees look solid but they are burning inside.

"Then all of a sudden bang, there's the tree gone and that's causing a lot of problems," he said.

"They're falling down across the road. We had powerlines down and access in these bush blocks is very hard."

Meanwhile, firefighters continue to battle a blaze in South Australia's Flinders Ranges, which is still burning out of control but no longer threatening homes.