Meanwhile, authorities have urged Australians to evacuate parts of the eastern states of Victoria and New South Wales to escape bushfires they fear are set to burn out of control this weekend.
There have been 10 deaths from the fires in NSW and Victoria so far this week, about half the total toll for the current fire season, and authorities have said the focus today is preventing more loss of life.
A total of 28 people are still unaccounted for.
Victoria declared a state of disaster across areas home to about 100,000 people, with authorities urging people to evacuate before a deterioration expected on Saturday.
"If they value their safety they must leave," Michael Grainger of the state's police emergency responders told reporters. "I'd suggest personal belongings are of very, very little value in these circumstances.
"These are dire circumstances, there is no doubt."
NSW Rural Fire Service Commissioner Shane Fitzsimmons says the 264,000-hectare Green Wattle Creek bushfire on Sydney's southwestern outskirts is a priority on Saturday.
"There is potential for the fire to break out, cross the (Warragamba) dam and move into the western suburbs of Sydney," he told reporters on Saturday morning.
"It has the potential to come out into more populated areas this afternoon."
Mr Fitzsimmons said crews have been working around the clock to contain the Green Wattle Creek blaze.
"Crews have been doing extraordinary work with backburning and the use of aircraft and machinery on the ground to try and lock that in," he said.
"That's one of our focus fires, of course, but I would say as a broader message be alert, be focused on any new fires today."
Extreme fire danger is forecast for six fire districts in NSW's southeast and the ACT, while severe conditions are forecast for Sydney, the Hunter and the central ranges.
There are some 137 bushfires burning in NSW on Saturday morning, with around 60 uncontained.
More than 3000 firefighters are on the frontline, with 31 specialist strike teams in place across NSW.
NSW Premier Gladys Berejiklian urged people to evacuate bushfire hotspots while they still have the time.
"I'm pleased to say that we've never been as prepared as we are today for the onslaught we're likely to face," she told reporters on Saturday morning.
"All of the major road networks are still open, but we can't guarantee that beyond the next few hours. So, there are still windows for people to get out."
The situation in Victoria
An emergency alert for Nowa Nowa in East Gippsland went out about 8.30am on Saturday.
"There is a bushfire at Buchan Valley that is not yet under control," the alert reads.
"The bushfire has escaped control lines at Mount Nowa Nowa and is spreading towards the Nowa Nowa township."
People in the town are being told to leave via Princes Highway towards Lakes Entrance.
The Buchan Valley fire has merged with several others during the past week, with several alerts in place for townships bordering the blaze.
Emergency warnings are also active for a 124,000 hectare blaze near Corryong in the northeast and for Biggara, Towong and surrounding communities.
There are several watch and act alerts in place for the same fires, including a 112,800 hectare fire that drove 4000 people to shelter on the beach at Mallacoota during the week.
The first evacuees from the holiday town arrived at Hastings port on Saturday morning, earlier than expected.
The 60 people on board HMAS Sycamore will be taken to a relief centre at a nearby Sommerville recreation ground.
HMAS Choules carrying 1100 people will be following the Sycamore.
"Both the Sycamore and Choules will re-supply and head back to Mallacoota," Emergency Management Commissioner Andrew Crisp told Nine on Saturday.
"It's not just the ships, we have a plan in place and we know the area is significantly impacted by smoke.
"We have Chinooks that can carry 50 people, they are ready to go based at East Sale the RAAF Base there, if the smoke clears we can get them in."
Blackhawks have also been flying aged and infirm people out of the fire grounds.
About 50 fires continue to burn across Victoria with more than 820,000 hectares destroyed - all mostly in the East Gippsland and northeast of the state.
There are 28 people missing in East Gippsland, in addition to two men confirmed dead in the fires.
Communities in the worst-hit areas have been urged to evacuate, with about 500 people at a relief centre in Bairnsdale on the western edge of the Gippsland fires.
Temperatures are expected to creep higher on Saturday, with parts of Gippsland forecast to hit 40C and areas of the northeast to reach 45C, before a gusty southerly change in the afternoon.
There are fears dry lightning storms will start more fires.
Total fire bans have been declared on Saturday for the Mallee, Northern Country, North Central, North East, East Gippsland, West and South Gippsland weather districts.
An unprecedented state of disaster was declared on Thursday, triggering powers introduced after the devastating 2009 Black Saturday bushfires, including allowing authorities to compel people to leave.
Areas covered by the declaration are the East Gippsland Shire, Mansfield Shire, Wellington Shire, Wangaratta Rural Shire, Towong Shire and Alpine Shire. It also covers Mount Buller, Mount Hotham and the Mount Stirling Alpine Resorts.
Evacuation alerts are in place across East Gippsland and in the Alpine region.
Total fire bans are in place across the north and east of the state.
With Reuters
