Fire authorities are preparing for worsening weather conditions throughout today and into the weekend as crews battle to quell blazes across the country.
A total fire ban is in place for New South Wales, the ACT and Victoria as the nation continues to suffer a record-breaking heatwave.
More than 95 fires are burning across New South Wales, with 18 out of control.
Authorities are particularly concerned about major blazes at Dean's Gap, south of Nowra, and fires at Yass and Sussex Inlet.
Bridie O'Connor from NSW's Rural Fire Service (RFS) says authorities are worried that strong winds will help fan fires across the state.
"The real threat is that these fires will get really pushed along, the wind will get behind them and push them along and they could once again start to threaten properties," Ms O'Connor said.
"They are not set to ease on Saturday and Sunday - we are going to be seeing some very, very high temperatures right throughout Friday and into the weekend, so there will be no reprieve for firefighters."
All walking tracks have been closed in the state's national parks with temperatures set to soar above 40 degrees Celsius.
Firefighters at Dean's Gap have been working to stop the blaze reaching .
The RFS says crews have used a special gel and are bulldozing containment lines to stop the fire from entering the range.
Meanwhile two teenagers have been refused bail after being charged with arson after nine fires had to be extinguished last night in bushland at Macquarie Fields.
In Victoria, crews are fighting a blaze that has broken out in grassland at Blampied, north-east of Ballarat.
Several trucks and three aircraft are attacking the fire that started in hot and windy conditions this afternoon.
Firefighters have contained a grassfire that was burning close to the Bass Highway, at Pound Creek, near Inverloch.
A smaller fire, near Yea, north of Melbourne, was brought under control after burning through 150 hectares.
A cool change has arrived in coastal areas of Victoria's south-west, but it is yet to move inland.
Tasmanian fire authorities are hopeful crews did enough work on Thursday to keep most of the state's fires under control.
Bulldozers and water-bombing helicopters are helping firefighters control bushfires in rough terrain in the state.
Only one of the 28 fires burning in Tasmania has communities on alert, with properties from Kellevie to Taranna still on a watch-and-act warning.
Paul Symington from the Tasmanian Fire Service says the groundwork has been laid ahead of warmer forecasted temperatures.
"It's been a fantastic effort today by all firefighters from all the different agencies, from Parks, Forestry and the private sectors," he said.
"Hopefully the work they have done today will make conditions a bit better and hopefully keep the fire within those current containment lines."
There are currently 22 fires burning across Queensland, but none are threatening communities.
Favourable conditions have helped firefighters contain a blaze on Bribie Island, north of Brisbane, that has scorched 2,000 hectares.