The navy has arrived off Mallacoota to rescue hundreds of tourists and residents caught up on the devastating fire emergency.

It comes as enormous queues form at service stations and supermarkets on the NSW south coast as holiday makers try to flee in a brief window of milder weather before conditions worsen again.

Authorities have less than 24 hours to move thousands of people from NSW's south and north-eastern Victoria before the fire risk is forecast to escalate again.

"We're expecting to see temperatures up into the high 40s, a westerly-northwesterly wind pattern will dominate which means it'll bring very hot, very dry air across the region," NSW Rural Fire Service Commissioner Shane Fitzsimmons.

Conditions on Saturday are forecast to be worse than on New Year's Eve, which left a trail of destroyed homes, businesses and utility lines in the region.

HMAS Choules anchored about 15 metres off Mallacoota, in Victoria's far north-east, on Thursday morning. It is loaded with supplies and ready to begin evacuations.

But the ship has capacity for only 500 people – there are thought to be 4000 stranded in the coastal town after Tuesday's devastating fires.

Victorian Premier Daniel Andrews said an "enormous amount of planning" was being done to decide who would get onto the ship, and how.

"This is no simple task and it needs to be done properly with safety as the paramount issue, but we will get some people out of Mallacoota today, we believe," he told ABC radio early on Thursday.

A second vessel, the MV Sycamore, which can carry a helicopter, was expected to arrive in the region later on Thursday.

RFS Deputy Commissioner Rob Rogers said it was a race against the clock to get tourists out before Saturday.

"We have so many fires still burning down there … and quite close to communities as well," he told the ABC.

"We won't get containment on those fires before Saturday."

Navy arrives as thousands flee bushfire zone in 'mass relocation'_1
Inset: Shopping for supplies in the dark at Narooma. Photo: Twitter/Jade Macmillan

Seven people have died since Monday night, taking the number of deaths this bushfire season in NSW to at least 15. One man has also been confirmed dead in Victoria.

Mr Fitzsimmons said on Thursday that at least 382 homes had been destroyed on the NSW south coast since New Year's Eve.

This number is expected to climb higher as damage assessment teams gain access into hard-to-reach areas.

In Victoria, a further 80 houses are thought to have been destroyed.

-with agencies