Thousands of Australian firefighters are once again on standby with dry westerly winds and temperatures above 40 degrees Celsius forecast for parts of New South Wales on Friday.
The past two days have brought cooler conditions, which has given some relief to firefighters battling more than 100 blazes throughout the state.
Fires are also burning in parts of Victoria, Tasmania and Queensland, after record temperatures earlier in the week.
On Thursday, hundreds of firefighters back-burnt and set up containment lines as they tried to beat rising temperatures. A total state-wide fire ban in New South Wales will be in force from midnight as crews prepare for severe fire weather on Friday and at the weekend, the ABC reports.
The mercury is set to reach the low to mid-40 degrees Celsius on Friday and the high 40s on Saturday. However, the fire danger is not predicted to reach the catastrophic level of last Tuesday.
The Rural Fire Service says cooler conditions on Thursday allowed crews to make inroads on several serious blazes and rest staff ahead of Friday.
The Weather Bureau predicts firefighters will be battling hot to very hot northwesterly winds, with temperatures reaching well above average. A cooler change is expected to bring temperatures back to normal by Monday.
Crews on Thursday worked to stop a bushfire in southern New South Wales from reaching a former military range scattered with unexploded bombs.
The Dean's Gap bushfire was out of control near Wandandian. More than 80 firefighters tried to contain the blaze which has burned through almost 6000 hectares.
Just 1km west of the Dean's Gap blaze is the Tianjara plateau, which was used by the Army as a practice bombing range for 30 years until the mid-1970s. It is now part of the Morton National Park, but unexploded ordnance remains scattered throughout the range.
Brett Loughlin from the Rural Fire Service says unexploded bombs would make it impossible to fight a fire.
"We can't do any water-bombing with aircraft or something like that in case the weight of the water when it hits the ground sets off any unexploded ordnance.
"So it's a total no-fly zone and that will mean [if] the fire gets into that area, there's nothing we can do for it except wait for it on the other side. That could compound our firefighting strategies."
Elsewhere, Rural Fire Service Commissioner Shane Fitzsimmons says there are three major blazes of concern in the south on Thursday - near Cooma and the village of Sussex Inlet, as well as a large blaze near Yass. Some 369,000 hectares has been burnt so far, with stock losses estimated at about 10,000.
Mr Fitzsimmons said many communities were yet to face the worst.
Meanwhile, police are continuing to investigate a fire near Lithgow in the Blue Mountains west of Sydney, which destroyed about 40,000 hectares on Wednesday. It is believed to have been deliberately lit.
Tasmanian search for bodies nears end
Police in Tasmania have almost wrapped up the search for bodies in bushfire-affected areas.
They have searched more than 850 properties, destroyed during the weekend by a number of blazes in the southeast of the state.
Acting Commissioner Scott Tillyard says even though fatalities cannot be ruled out, there are no longer any serious concerns about missing people.
On Thursday, the fire service warned that a bushfire in the southeast is continuing to behave erratically and could approach communities. More than 120,000 hectares and 150 homes have been devastated by the fires that began last week.
The threat from major blazes in the state's north and upper Derwent Valley has eased, but a fire that started at Forcett in the southeast remains a serious concern. The fire service says people must remain vigilant, even if a fire is contained, the ABC reports.
Meanwhile, nearly 50,000 hectares of a world heritage area in south-west Tasmania have been destroyed in one fire which is still burning out of control and tracks in the area remain closed.
Pilot Nicholas Hoyle flew a team from the Parks and Wildlife Service over the area on Tuesday and said they saw flames up to six metres high. He said smoke from the blaze could be seen more than 100km away.
A New Zealand helicopter pilot working with the Tasmanian Fire Service to help control dozens of fires still burning says this season of bushfires is possibly the most challenging he has ever been involved in.
Dave Latham has been a helicopter pilot contracting in Australia for more than 11 years and has worked in some of the country's worst fires, including in 2009 when 173 people died in bushfires throughout the state of Victoria.
Victoria on alert
Victoria is bracing for another high alert day on Friday as temperatures reach the low 40s in parts of the state.
Acting Premier Peter Ryan visited Snake Valley, west of Ballarat, on Wednesday which was at the heart of the Chepstowe bushfire that destroyed nine homes and injured 12 people.
Mr Ryan said the fire was a clinical example of the type of blaze that had been talked about for several months.
"The prospect this season is of fast running grass fires and that is what happened yesterday. In a blink it was on top of this community and 1200 hectares have been burnt out, this is exactly what we have talked about."