Defence personnel are ready to pounce on bushfire grounds as extreme conditions grip Victoria, NSW and the ACT.
Emergency warnings are also in place on Kangaroo Island as crews battle out-of-control blazes.
Prime Minister Scott Morrison has instructed the Chief of Defence to prepare his troops.
"I've given them very clear instructions that they are to stand ready to move and support immediately in the event that they are needed," Mr Morrison told reporters on Friday.
"They will move and ensure they can provide support as swiftly as they can, but again, working in concert with local state and territory authorities."
Hot weather and strong winds have created dangerous fire conditions in southern NSW and Victoria.
The defence force has been told to work alongside firefighters and emergency services should their help be required.
Troops aboard Chinook helicopters have spent several days clearing roads, restoring communications and dropping off supplies to isolated communities.
Defence personnel have also dropped fodder to sheep and cattle in rural towns and helped bury thousands of livestock killed in the blazes.
"There was a lot of work going on with that yesterday," Mr Morrison said.
"That has been already taking place on Kangaroo Island but that's obviously hampered at present because of the fire front that they are confronting there."
The extreme conditions also forced the closure of several Service Australia pop-up centres set up to help bushfire victims access support payments.
Meanwhile, the states have each been given millions of dollars in commonwealth cash to immediately provide to local council areas worst affected by the fires.
The federal government is working with the small business lobby to help shop owners and tourist operators devastated by the fires.
It has also developed a mental health strategy expected to be announced in coming days.
In the longer term, the prime minister says any national inquiry into the bushfires needs to be wide-ranging and examine what impact climate change has had on the crisis.
Mr Morrison is weighing up calling a royal commission into the disaster, which would also look at hazard reduction burns and national coordination.
"I think Australians, because of the scale of this particular disaster, will be looking for something more holistic," he told 2GB radio.
"That's not the focus right now - today there are severe and extreme fire forecasts in Victoria and NSW - but down the track, that's what premiers and I will discuss."
The bushfires have killed 27 people and destroyed more than 2000 homes.
The federal government has committed at least $2 billion towards the recovery effort.
But while the prime minister acknowledges there is an appetite to examine the impacts of climate change, he will not consider a stronger commitment to carbon emission reductions.
Mr Morrison said Australia was already "meeting and carrying" its burden on greenhouse gas emissions.
Australian Associated Press