Fretting families and tireless firefighters have rung in the new year watching a cool change wreak further havoc across NSW's fatal firegrounds.

As fire authorities predicted the loss of multiple homes, a telecommunications outage left families on New Year's Eve unable to contact loved ones on the fire-ravaged south coast.

"No communication is a rarity in today's world so it's an uncomfortable feeling," Melbourne man Nic Baxter told AAP on Tuesday evening, as he waited to hear from his father in Batemans Bay.

Australia bushfire crisis Credit: Sam Mooy / Getty Images

"Fortunately, he is located in an area where I'm sure he is OK, but still very uncomfortable.

"I don't think I can celebrate NYE to be honest, too much on my mind thinking about the fires and family."

NSW Police earlier confirmed all power had been lost from South Nowra to Moruya and "potentially beyond", affecting at least 46,000 people and the supported telecoms network.

In the video below: The moment NSW firefighters truck gets overturned by flames

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Conditions ease

Fire conditions are expected to ease on Wednesday after a cool change, bringing gusts of up to 80km/h and dry lightning strikes, crossed the state.

Before 7am no fires were at emergency warning level, but eight - including the 230,000-hectare Currowan blaze on the south coast and the 64,000ha Clyde Mountain fire ringing Batemans Bay - were at watch and act level.

Before 7am Wednesday no fires were at emergency warning level Credit: 7NEWS

Waterbombing aircraft helped efforts to stop a 250ha blaze reaching residential homes at Blue Haven on the Central Coast.

Australia bushfire crisis Credit: Sam Mooy / Getty Images

"We'll have more conscience flights up ... along with the extraordinary firefighting effort," NSW Rural Fire Service Commissioner Shane Fitzsimmons told reporters on Tuesday afternoon.

"We are truly grateful and appreciative for all everyone is doing.

"We've seen a very responsive, very decisive community understanding and accepting an extraordinary level of disruption from what is proving to be some very destructive and deadly bushfires."

Total fire bans

Total fire bans are in place for Southern Slopes, Southern Ranges and Central Ranges on Wednesday, ahead of predicted worsening conditions over the weekend.

Multiple property losses are likely but it will take several days to assess all the losses, the RFS says.

The towns of Fishermans Paradise, Broulee and Mogo, which is home to a popular zoo, have experienced significant damage.

Road closures

Meanwhile, major roads, including several parts of the Princes Highway linking south coast communities, are likely to remain closed for some time due to hazards.

Rural Fire Service (RFS) firefighters prepare for property protection near the town of Sussex Inlet on December 31, 2019 in Sydney, Australia. Credit: Sam Mooy / Getty Images

Death toll

Communities are also mourning three lives lost since Monday.

Firefighter Sam McPaul, and young father Patrick Salway and his dad, Robert Salway, died in two incidents in the state's south.

"We are broken," Renee Salway told friends via Facebook on Tuesday night after her husband's death was confirmed.

"I will see you again Patrick, my best friend."

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A 72-year-old man remains missing 50km north of Cobargo but police have been unable to safely reach his property.

Premier Gladys Berejiklian is expected to visit south coast communities on Wednesday after receiving a briefing at RFS headquarters.

Late on Tuesday, environmentalist Greta Thunberg weighed in on the NSW fires, tweeting the ironic hashtag #ThisIsFine with a video of a fire front passing over a Fire and Rescue NSW crew's truck.

The crew from Wyoming had been cutting a path along a dark, smoky road south of Nowra on Tuesday before the fire front closed in on their left flank and passed over them.

Two trucks nearby were destroyed in South Nowra in a similar incident but the firefighters inside were unharmed.

More than 100 fires were burning across NSW as of midnight on Wednesday, with over half of those uncontained.

Victoria

Destructive bushfires have burnt through more than half a million hectares in Victoria's East Gippsland and more blazes have started.

Seven emergency alerts remain in place in Victoria's east, four people are still missing and thunderstorms continued to create dry lightning, sparking new fires overnight.

Commuters are seen as a Rural Fire Service (RFS) helicopter lands on the Princes Highway near the town of Sussex Inlet on December 31, 2019 in Sydney, Australia Credit: Sam Mooy / Getty Images

"The fire threat in our state has increased overnight. There were some more thunderstorms come through with dry lightning and we have a number of new fires in Mount Hotham, King Valley and we have 45 going fires in the east of the state," Emergency Management Commissioner Andrew Crisp told ABC News on Wednesday.

Three fires in East Gippsland have already joined and Mr Crisp said there is worry that a fire burning in northeast Victoria at Corryong could join with them too.

Some blazes are now spreading between NSW and Victoria.

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The fire that drove thousands of people to shelter on the beach at Mallacoota is now about 100,000 hectares and moved into NSW.

Mr Crisp said 24 structures have been destroyed at Buchan, 19 at Sarsfield, 10 at Mallacoota and 10-to-15 at Cudgewa.

Military help

After a request from Premier Daniel Andrews on Tuesday, military personnel will start arriving to help with the relief effort.

Aircraft including Black Hawk helicopters are expected to land in the east of the state on Wednesday with other aircraft and naval vessels due in the coming days.

Residents watch the developing conditions near the town of Sussex Inlet on December 31, 2019 in Sydney, Australia. Credit: Sam Mooy / Getty Images

The aircraft are expected to help move fire crews, supplies and help with evacuations as needed.

Naval vessels including the HMAS Choules left Sydney bound for the East Gippsland coast on Tuesday evening and training vessel MV Sycamore has also been deployed.

People stranded

It comes as thousands of people remain stranded in remote communities because of blazes as firefighters continue their efforts.

Parts of the Princes Highway will be opened on Wednesday to allow people to escape.

The state government also announced a bushfire response task force to avoid red tape in dealing with fallout from the blazes.

Premier Daniel Andrews and Emergency Services Minister Lisa Neville will visit the region on Wednesday.