'We Are Not Out Of The Woods': Bushfires Ravage Tasmania and Victoria

Firefighters in Tasmania and Victoria continue to fight out-of-control blazes across their states as extreme summer temperatures offer no relief.

An uncontrolled wilderness bushfire raging in Tasmania's southwest is expected to continue its fury over the weekend as firefighters battle to put it out.

The Gell River fire, west of the Tasmanian capital, has burned through almost 15,000 hectares of bush but no longer poses an immediate risk to properties, the Tasmania Fire Service states.

But residents were warned of a risk of embers from the blaze, burning about 20 km northwest of the communities.

An advice warning remains in place on Saturday for Maydena, Tyenna, Mt Field, National Park, Bushy Park, Ellendale, Westerway and Fentonbury.

Severe fires continue to burn across Tasmania. Image: AAP.

Parks and Wildlife Service's Paul Black told reporters on Friday the fire was expected to subside overnight as the wind change and cold front moved in.

"Over the next couple of days we'll have a much more moderate fire behaviour, which will give our crews an opportunity to make a very good assessment of what the fire has got to and what our control strategies should be from here on in," he said.

"The area has a significant amount of smoke and cloud over it which makes it difficult to determine that western boundary ... but there will be more information coming out about that for 24 hours."

Sprinkler lines have been set up to protect some communities in case the fire heads in their direction while more retardant drops, backburns and water bombing could happen.

"We are not out of the woods. There is a significant fire risk," Tasmania Fire Service chief officer Chris Arnol said on Friday.

Hobart is expected to hit a top of 22C on Saturday.

Fires Rage In Victoria As Melbourne Cools

It's been less than a day since Melbourne tipped over 42C but temperatures have plummeted as fires continue to burn across parts of the state.

The city is headed for a top of 21C on Saturday just a day after being belted with scorching heat while some northern centres hit 46C before a cool change swept through.

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The milder conditions are expected to bring much relief for firefighters still battling a nearly 600-hectare blaze near Rosedale, in the state's east, which has been burning overnight.

Emergency services warned Fulham, Kilmany, Kilmany South and Pearsondale residents to "watch and act" if the situation changes about 3.40am on Saturday.

Residents in Stradbroke West, Willung and Willung South have been told to do the same.

Meanwhile, a third watch and act warning has been issued for the areas of Ancona, Merton and Strathbogie, with residents told to keep an eye on a grass fire burning nearby.

Victoria Police told AAP it was investigating the cause of the Rosedale fire.

Emergency Services Minister Lisa Neville warned on Friday that the "danger period is not over" with fire still in the landscape and scope for more blazes.

Featured Image: AAP.