The New Zealand Defence Force (NZDF) personnel in Australia who are helping to fight the bushfires have arrived in their base-town Nowra, New South Wales (NSW), where vital work awaits them.

They will go wherever they're needed to move people and deliver crucial supplies, but they'll also be crucial to NSW firefighters. From the air, they can see where the fire is spreading and which communities stand in the way.

An NZDF personnel member said it was overwhelming to be there.

"It's just so hard back home to comprehend the scale of the devastation that's happened through these fires," she said.

On the ground in Victoria, Belinda Attree was filmed as she drove down a road with flames ravaging the land either side of her.

"Oh my god, this is the scariest thing I have ever done," Attree is heard saying, as she filmed her terrifying escape.

Once she makes it through the inferno, her relief is clear.

"Oh thank f**k I'm through, thank f**k I'm through, thank f**k I'm through."

The Corryong farmer lost livestock in the blaze, but was able to make it out safely herself.

"I was absolutely petrified. Just there was flames everywhere and I knew the one thing I had to do was just not stop," Attree said after the incident.

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Temperatures are forecast to climb to the 40C mark, and fire crews are preparing once again for several tough days ahead.

"We have forecast conditions of extreme danger, very significant fire activity is likely, off the back of a hot day today, a hot day tomorrow," Premier for Victoria Daniel Andrews said.

Bushfires intensified on Kangaroo Island on Thursday, with thick smoke shrouding the island.

The Wildlife Park is part of the area under threat, but staff are determined to stay and protect the 700 animals in their care, including hundreds of fire-injured koalas.

Some of the island's residents are making the early decision to leave after officials said the situation there "is not a drill".

"This is a real danger zone. The family and I are getting out probably tonight," one resident said.

But there is some relief after the town of Mallacoota in Victoria has been fully evacuated after being cut off for a week.

Kiwis were among the first rescuers there and brought supplies to stranded residents from a ship.

One person rescued said being in the town was like "Armageddon".

"Everyone's using that term, and I've never been through it, but it's as good as I can describe it."

The state of Victoria has extended a state of disaster, which now covers almost the entire eastern half of the state.

Temperatures are expected to sit in the 40s and the flames will be fanned by very strong winds. There's potential this may push fires in a new direction and put new homes and communities under threat.