Four people are unaccounted for and homes have been destroyed as fires rip through Victoria's East Gippsland.
Premier Daniel Andrews confirmed the missing people at a press conference on Tuesday morning in Melbourne.
The missing people are not firefighters, he said.
"There are four people unaccounted for. We can't confirm their whereabouts," Mr Andrews told reporters.
Mr Andrews said he would request support from the Australian Defence Force to assist with emergency efforts as the bushfire crisis develops.
Mr Andrews told the news conference he had exchanged text messages with Prime Minister Scott Morrison and was in discussions with the ADF about what logistical support they could provide.
Evacuation by sea had been under discussion, as around 4000 people are sheltered on the beach in the township of Mallacoota as the fires approached on Tuesday morning.
NSW fire crews under the pump
Almost 100 blazes continue to burn across NSW, with dozens uncontained and eight on Tuesday morning at "emergency" level.
Extreme fire danger is forecast for the Southern Ranges, Illawarra and ACT on New Year's Eve while surrounding regions - including Sydney, the Hunter and the far south coast - are set for severe fire danger.
Total fire bans are in place for more than half of the state's 21 fire districts.
The Clyde Mountain fire, to the south of the persistent 226,000ha Currowan blaze, is now impacting Batemans Bay and likely to further deteriorate when southerly winds arrive in the coming hours. Massive traffic queues to escape the township have popped up on Beach Road.
Those in the town have begun evacuating to the beach.
The Dunns Road fire near Tumut and the Badja Forest Rd fire near Cooma appear set to be among the blazes on Tuesday to expand most significantly, with the latter potentially impacting upon Bermagui and around Bega.
Fire prediction maps suggest the Green Wattle Creek fire, which has already scorched 227,000ha, may cross the Hume Highway near Bowral.
Volunteer firefighter mourned
A volunteer firefighter who died when his truck flipped amid a "fire tornado" at a NSW-Victoria border town was expecting his first child in May.
Samuel McPaul died on Monday just before 6pm when the truck he was travelling in crashed at Jingellic, about 110km east of Albury in NSW.
An emotional Rural Fire Service commissioner Shane Fitzsimmons on Tuesday said the 10-tonne truck was hit by winds so extreme at the 26,000-hectare Green Valley fire that it flipped on its roof.
Two male colleagues in the fire truck - aged 39 and 52 - were injured and taken to hospital. The 39-year-old was airlifted to The Alfred Hospital in Melbourne and remains in a serious condition.
A command vehicle was also blown over, injuring one other firefighter.
On the same fire ground, two firefighters suffered burns to their faces and airways and were airlifted to Concord Hospital.
"Crews described what they experienced as truly horrific, an extraordinary wind event, describing it as a fire tornado or the collapse of a pyro-convective column that had formed above the main fire front,"Mr Fitzsimmons told reporters on Tuesday.
"That's resulted in cyclonic-type winds that have moved across the fire ground and has literally lifted up a 10 or 12-tonne fire truck."
"This brings home to us what NSW is going through - every fire front is a threat to life, a threat to people's life as they know it," NSW Premier Gladys Berejiklian said.
Mr McPaul is the third NSW volunteer firefighter to die this bushfire season. Geoffrey Keaton, 32, and Andrew O'Dwyer, 36, died on December 19 when a tree hit their tanker as they were travelling southwest of Sydney.
WA bushfire continues to burn
A large bushfire is still burning within containment lines in Western Australia's south with a watch and act warning in place for local residents.
The blaze in the state's Great Southern region has scorched more than 32,000 hectares since being sparked by a lightning strike on Boxing Day.
It is burning within containment lines with about 175 firefighters on the scene in an effort to bring it under control.
Areas still considered at risk include the Stirling Range National Park, northern parts of the City of Albany, southern parts of the Shire of Gnowangerup, northeastern parts of the Shire of Plantagenet and eastern parts of the Shire of Cranbrook.
Many roads remain closed and motorists are urged to avoid the area.
Stirling Range National Park, Bluff Knoll Recreation Site, Moingup Springs Campground and Mt Trio bush camp and caravan park are also closed.
Island fire a worry in SA
South Australian fire authorities said they have the upper hand on a number of bushfires, though two on Kangaroo Island are still a concern.
A watch-and-act message remains in place for fires at Ravine on the western end of the island as they continue to burn towards the north coast.
Local residents have been urged to leave if they are not prepared to defend their properties.
Advice messages are now in place for a fire at Keilira, in the southeast, and for one burning at Miltalie on Eyre Peninsula.
Cooler conditions which moved across SA on Monday afternoon have allowed fire crews to get the upper hand in both areas.
An advice message also remains in place for the large Adelaide Hills bushfire which has destroyed 25,000 hectares since it was sparked amid catastrophic conditions 10 days ago.
More than 120 fires were sparked across SA on Monday, prompting the CFS to send more than 600 volunteers and 150 fire trucks into the field.
It said firefighters, volunteers, staff, support personnel and allied agencies, along with hundreds of families at home, had done an amazing job in keeping the impact of the challenging conditions to a minimum.
Homes lost in Tasmania bushfires
A bushfire has destroyed structures in Tasmania but authorities say it's too early to know if homes are among them.
Tasmania Fire Service (TFS) crews will on Tuesday further examine the fire ground at Pelham in the state's south, about 50km north of Hobart.
"Seventy per cent of the fire ground has been assessed. We've got some structural losses," TFS Chief Officer Chris Arnol said.
"We're not sure if any homes have been lost. It could be sheds it could be homes, we don't know.
"Access is difficult with that fire, with smoke conditions and some power infrastructure down."
Another fire in the northeast threatened the town of Fingal, where 20 to 30 homes were protected successfully.
Dry lightning sparked both fires, with the Bureau of Meteorology recording more than 400 ground strikes as thunderstorms crossed the state.
The storms brought some rain but not enough to have any impact on the fires.
The Fingal and Pelham fires were at 'watch and act' alert level at lunchtime on Tuesday.