Fire crews have warned they can't get to everyone as unprecedented blazes swept through NSW and thousands of people were evacuated overnight in two states.
Residents were reportedly trapped in their homes in NSW as overnight wind changes pushed firefronts in new directions, sparking fresh evacuations in numerous towns and suburbs.
"Unfortunately, many people have called for help but due to the size and speed of the fires we couldn't get to everyone, even by road or helicopter," NSW Rural Fire Service warned in a tweet.
"If you've been affected or know someone who has, use https://register.redcross.org.au #nswrfs"
Residents described scenes of Armageddon as evening skies burned orange, flames grew like skyscrapers and dark clouds choked the air.
The intensity of the extreme infernos on the NSW north coast even created their own weather conditions as flames became "more intense – and more dangerous", the NSW Rural Fire Service warned.
The so-called fire clouds (pyrocumulus) can produce lightning and thunderstorms as the thick dark clouds develop over fires.
"These are extremely dangerous. Do not be caught in the open," NSWRFS warned.
Emergency warnings have been issued in NSW from the Blue Mountains to the Queensland border while in Queensland fires are raging from the Gold Coast to the Sunshine Coast, including a suspicious blaze that was sparked in the Brisbane city suburb of The Gap on Friday.
Firefighters are warning to expect widespread property damage, with reports of at least two properties destroyed near Coraki in northern NSW as more than 80 bushfires raged in the state as of midnight – half of them uncontained – pushing thousands of firefighters to their limit.
Nine of the NSW fires were at "emergency level" Saturday morning while many remained "erratic and dangerous".
Early Saturday morning in Queensland, residents were ordered to "leave now" in the regional towns and suburbs of Thornton and Lefthand Branch near the Lockey Valley; Noosa North Shore, Cooroibah and Tewantin on the Sunshine Coast and Lower Beechmont near the Gold Coast.
Others were told to prepare to leave at Clumber and Moogerah (south of Beechmont), Tarome, Jimna, Laidley Creek and Mulgowie.
About 50 fires were burning across the Sunshine State in hot, dry and windy conditions.
NSW Rural Fire Service Commissioner Shane Fitzsimmons said emergency workers were facing never-before-seen circumstances.
"We are in uncharted territory … we've never seen this many fires concurrently at emergency warning level," he said.
"We can certainly see some of the aerial footage and the vision coming through which is identifying some widespread property damage and destruction right across multiple firegrounds," Mr Fitzsimmons told ABC on Friday night.
MidCoast Mayor David West, who lives in Brimbin, said he had never seen anything like the fire in his area.
"I'm looking at a sky that's screaming danger, that's saying 'get out of my way, I'm going to kill you'," he said.
"I know that sounds melodramatic but it's not. This is a fire that's devouring everything in its path."
Mid-Coast Council Mayor David West told the ABC 92,000 people in the major centres of Forster, Crowdy Bay and Harrington were affected.
"I'm looking out of my office window and all I see is what I'm assuming people in London saw during the Second World War — it's a horrible, horrible sight," he said.
NSW can expect a brief reprieve in conditions as temperatures cool over the weekend, but temperatures are expected to rise significantly from Monday.
A cool change is also expected over much of southern Queensland by Saturday morning, the Bureau of Meteorology's Jess Gardner said.
But fresh winds can make firefighting difficult, she added.
Hotter temperatures, which have fanned the flames around the south of the state, are expected to move further north on Saturday.
Meanwhile extremely hot, dry and windy conditions are expected to lash parts of Western Australia on Saturday, increasing the risk of bushfires in the state.
Northern and western parts of WA will cop the worst of the weather, with an extreme fire danger rating expected to be declared in three regions.
The Bureau of Meteorology has tipped the west of the state, including Perth, will get northeasterly gusts, ahead of a northwesterly change in the afternoon.
More moderate winds are expected in the north, with a fresh afternoon sea breeze likely to hit the Pilbara coast.
An extreme fire danger rating has been forecast for the central west, east Pilbara coast and west Pilbara coast regions. Under this rating, any fire that takes hold will be uncontrollable, unpredictable and fast-moving.
A severe fire danger rating – one level below extreme – is forecast for the lower west district including Perth, the west Kimberley coast, Kimberley inland, east Pilbara inland, Ashburton Island, Gascoyne Inland, the North Interior and Mortlock districts.
A bushfire was burning at a small town in WA's Wheatbelt region on Friday.
An emergency warning was in place for the blaze at Regans Ford, more than 100km north of Perth, for almost three hours before the warning was reduced to a watch and act level.
A possible threat to lives and homes remained late on Friday, however, with fire still out of control and unpredictable.