At least 19 people have been confirmed dead, with 29 still missing, as more than 1400 homes are lost to bushfires across Australia.

The death toll could rise dramatically as grave fears grow for the 28 people unaccounted for in Victoria's fire-ravaged east where 50 fires continue to burn.

Another person is missing in NSW where almost 130 bushfires – 70 uncontained – are raging and the number of homes destroyed since New Years Eve has jumped to 449, the Rural Fire Service confirmed on Friday.

Sixteen people are now dead from the region's blazes. A body believed to be that of a 72-year-old man who went missing in Belowra, north of Cobargo, was found in a car, raising the NSW death toll to eight since Monday.

Ferocious fires which have so far torched 3.6 million hectares and destroyed 1365 homes, are predicted to spread on Saturday as strong winds and hot weather place many fire zones under ember attack.

East Gippsland is among six local government areas that Victorian Premier Daniel Andrews has declared a state of disaster.

The emergency was also issued for Mount Buller, Mount Hotham and Mount Stirling Alpine resorts as high temperatures and strong winds loomed.

More than 180 firefighters from the US and Canada are also being brought in to help exhausted Victorian crews.

"These are unprecedented times," Mr Andrews said.

"We've not had such large-scale fire activity, such a big fire edge, so many going fires, and then get another wave of really challenging weather a week or so later."

‘Unprecedented times’: Grave fears held for missing Australians as NSW, Victoria continue to burn_1
Inset: Prime Minister Scott Morrison tours a fire devastated Wildflower farm in Victoria. Photo: AAP

Smoke from the East Gippsland fires has enveloped parts of Victoria, particularly Melbourne, causing hazardous air quality levels.

An evacuation alert remains in place for northeastern communities including Biggara, Tintaldra, Towong, Towong Upper, Walwa, Berringama, Burrowye, Koetong, Lucyvale, Nariel Valley and Shelley.

"The strong message from those who didn't leave (last weekend) is that they wish they had left," Emergency Services Minister Lisa Neville said.

"The fires were of such ferocity and intensity that it was very traumatic and people felt their lives were absolutely at risk.

"You should leave to save your life. If you don't we will be sending out police to make sure you've got the message."

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An emergency warning has also been issued for South Australia tourist hotspot Kangeroo Island, where an uncontrolled blaze to the west is posing a serious threat to human life.

"You are in danger. Act now. Identify where you will seek shelter, preferably in a solid building. Only leave if your path is clear to a safer place," the Country Fire Service said.

"Heat from the fire can kill you well before the flames reach you. Don't enter this area as firefighters are now unable to prevent the fire spreading."

-with AAP