Weary fire crews have welcomed favourable weather conditions as they continue to battle bushfires in several states.
But they're preparing for another dangerous fire day tomorrow, with total fire bans in place for Victoria, New South Wales and Tasmania.
Victoria braces for high temps
Authorities will be keeping a close eye on two blazes in the southern state, with temperatures of 42C expected in some areas, and north-westerly winds of up to 50km/h forecast.
Two districts - the Wimmera and north central - will have extreme fire danger.
There are 12 fires in Victoria, with two of concern to authorities, Fire Services Commissioner Craig Lapsley said.
Fire crews hope to have a fire at Kentbruck in the far southwest contained by 8am (AEDT) on Friday.
"That would be an ideal position based on the forecast weather conditions for tomorrow," he told reporters at the State Control Centre in Melbourne.
Mr Lapsley said significant resources would be on the Kentbruck fire, which has been going for nearly a week, to ensure it remained contained.
Crews will also keep a close eye on a fire at Goroke in the Wimmera region, which began on Tuesday and became active again on Thursday.
It was contained by 4pm on Thursday, but with extreme fire conditions forecast for Friday, the fire will be closely watched by authorities.
Conditions in the north central total fire ban district will also be extreme on Friday, while the rest of the state will face severe fire danger, Mr Lapsley said.
"That means we will see similar conditions to last Friday, elevated fire potential and if a fire does start it would take little for it to become uncontrolled in all parts of Victoria, with dry conditions and the weather," he said.
He said Victoria is very dry particularly in central and western areas.
"We have already seen that fires have actually taken hold without a lot of wind, or a lot of temperature," Mr Lapsley said.
"So tomorrow with temperatures being high, the winds being north-westerly and 40-50km/h means that fires will move very fast and will be out of control within a very short time of taking hold."
Mr Lapsley said firefighters was also keep a close watch on lightning predicted for overnight Thursday.
He urged people in bushfire areas to be prepared and have a fire plan and to listen to the radio, use the CFA website and the Bushfire Information Line.
Crews battle blazes in Tasmania
Firefighters are continuing efforts to establish containment lines on key bushfires in Tasmania.
With the state's fire service dedicating most of its resources to the major, uncontrolled fire around the Tasman and Forestier Peninsulas in the state's south-east.
Crews are working with Forestry Tasmania to contain major blazes in the state's north and in the Upper Derwent Valley.
The service's John Holloway says resources are being concentrated on the large fire in the south-east which has already burnt 20,000 hectares and destroyed 128 homes.
He is urging people to remain vigilant despite the cooler weather conditions.
"The containment lines on most of these fires under advice are not well established yet and they are very dependent on how strong the wind is," he said.
"So anybody in those areas needs to keep an ear out, needs to keep listening to the advice we are putting out because they could well get worse and affect the people close to them through the day."
He says crews, many of whom are volunteers, are eager to contain the blazes which began last week.
"They're tired, they're really keen to continue helping and they know there's a lot of hard work ahead of them."
NSW firies race against time
Making the most of cooler conditions, firefighters in New South Wales got on top of the bushfires to such an extent on Thursday that there were no emergency or "watch and act" alerts in force.
Of the 120 fires still burning in the state, only 17 remained uncontained.
But the Bureau of Meteorology forecast a return to heatwave conditions across large parts of the state from Friday, after a two-day lull.
Rural Fire Services (RFS) Commissioner Shane Fitzsimmons said much work remained to be done into Thursday night.
"It is going to be hot," he said, with temperatures expected to be in the low to mid 40s on Friday, and the mid and high 40s in western areas on Saturday.
The RFS has declared a statewide total fire ban will be in place for Friday.
The one piece of welcome weather news for firefighters was the prospect of lighter winds, after gusts of 70km/h and more hampered their efforts earlier this week.
"Fortunately, at this stage, all the indicators are we're not expecting the sorts of catastrophic conditions that we experienced back on Tuesday," said Mr Fitzsimmons.
But he warned wide areas of the state would experience high, severe and even extreme fire danger conditions.
That included northern NSW, the Great Dividing Range, the eastern seaboard and the Riverina.
So far only one house has been lost in the fires, at Yarrabin in the Cooma-Monaro region, but around 370,000 hectares have been burnt and an estimated 10,000 sheep worth $1 million have died.
Three fires were still causing concern on Thursday.
More than 100 firefighters were working to contain the Deans Gap fire south of Sussex Inlet, in the Shoalhaven.
It has burned through 5700 hectares and coastal village residents have been urged to remain vigilant as the fire risk builds towards the weekend.
"We need to get a really good handle on that fire before high fire danger conditions return," an RFS spokeswoman said.
The Yarrabin fire burning in the Kybeyan Valley was still uncontained after burning through 9400 hectares and firefighters were working to protect rural properties under threat.
Another uncontained fire at Cobblers Road, 10km west of Yass, has slowed and while not threatening properties, it was approaching an electricity transmission line.
Police hunt Victorian serial arsonists
As firefighters in Victoria work around the clock protecting properties and lives from bush fires, police are hunting arsonists responsible for at least six suspicious fires in Melbourne's north-west.
Crews were called to three separate grass and rubbish fires at an industrial estate in Balfour Avenue, Sunshine North early this morning.
Qld - Fire crews on alert
Fire authorities say Bribie Island residents will be kept informed of any threats to property as a large bushfire continues to burn north of Brisbane.
Sixteen fire crews spent the night strengthening containment lines around the blaze.
Incident Controller Noel Harbottle says scorching temperatures and unpredictable winds again today will test firefighters.
"Yesterday there was a lot of work done to protect the community of Bribie Island and we did a lot of back-burning to ensure that the properties, and in particular White Patch were safe," Mr Harbottle said.
"Today we'll continue to monitor those containment lines with our Queensland Fire and Rescue Service (QFRS) people.
"We'll make sure that people of Bribie Island are informed and that they're not at risk," he said.