An eighth person since Monday evening has also been confirmed dead after police found a missing 72-year-old man's body by a Belowra road.
That weather will create conditions officials say will be as bad as - if not worse than - Tuesday, the deadliest day in a months-long brush fire crisis.
The premier revealed the second death while announcing a state of disaster has been declared for six local government areas and three alpine resorts confronted by fires.
The declaration, which entails powers introduced after the devastating 2009 Black Saturday bushfires, allows authorities to compel people to leave.
One ship was headed for the coastal town of Mallacoota in Victoria, where around 4,000 people have been stranded on the beach front since New Year's Eve when they watched much of the town burn down.
"If you can leave, you must leave".
"We have to remain vigilant", he said.
Areas covered by the declaration are the East Gippsland Shire, Mansfield Shire, Wellington Shire, Wangaratta Rural Shire, Towong Shire and Alpine Shire.
Visitors are being warned to leave before Saturday, which is forecast to bring gusting winds and temperatures soaring above 40 deg C.
"We have a small window of opportunity", Assistant Emergency Services Commissioner Deb Abbott told reporters on Thursday.
Temperatures are expected to hit 40C at Gippsland and areas of the northeast are due to reach 45C, and a gusty southerly wind change has started.
Australian authorities on Saturday were racing the clock to contain 48 fires across the state of Victoria before unfavourable conditions move in.
"There can be significant fire activity even when conditions are fairly light in terms of winds", Bureau of Meteorology senior forecaster Tom Delamotte told AAP.
Blazes still threaten communities in Victoria's bushfire-ravaged east where six people remain missing and nearly a million hectares have been destroyed.
About 24 communities are isolated and reaching them to deliver supplies has been hard.
"These are unprecedented times", Mr Andrews said.
Australian Prime Minister Scott Morrison briefs the media following meetings in Sydney on October 9, 2019.
The New South Wales (NSW) Rural Fire Service on Thursday morning declared a "tourist leave zone" stretching about 200 kilometres from the popular holiday spot of Bateman's Bay along the picturesque coast to neighbouring Victoria state, where people are also being urged to flee.
The leader will visit East Gippsland on Friday.
None of the blazes are now burning above the watch and act level, the second-highest bushfire alert.
The fire there, straddling the border with NSW, has burnt more than 121,600 hectares.
Major highways have been closed for days, phone and powerlines are down, and residents have been told not to drink tap water amid contamination fears.
"This is a marathon event and we expect to be busy managing these fires for at least the next eight weeks".
More than 1,000 people arrived in Melbourne safely after being evacuated from Mallacoota on the HMAS Sycamore and HMAS Choules.
This season's blazes have destroyed more than 1,300 homes and scorched over 5.5 million hectares (13.5 million acres) across the country - an area far greater than Denmark or the Netherlands.