Australia authorized the forced evacuation of residents Thursday amid a mass exodus of tourists from fire-ravaged coastal communities, as the country braces for a weekend heatwave expected to fan deadly bushfires.

Fire and rescue workers observe the condition of the bushfire in the smoke-shrouded Blue Mountain area, New South Wales, Australia, Dec. 21, 2019. (Xinhua/Bai Xuefei)

Catastrophic blazes ripped through the country's south-east on New Year's Eve, killing at least eight people and stranding holidaymakers.

New South Wales (NSW) Premier Gladys Berejiklian declared a seven-day state of emergency that allows for forced evacuations beginning Friday, for the third time in Australia's most populated region this fire season.

"We don't take these decisions lightly but we also want to make sure we're taking every single precaution to be prepared for what could be a horrible day on Saturday," she said.

It came as the NSW Rural Fire Service declared two "tourist leave zones" stretching almost 300 kilometers from the town of Nowra along the picturesque coast to neighbouring Victoria state, where people are also being urged to flee.

Residents and visitors in two inland areas - which include popular holiday resorts in the Snowy Mountains - were also told to leave, with people given less than 24 hours to evacuate before a heatwave brings gusting winds and temperatures above 40 degrees Celsius.

That weather will create conditions officials say will be as bad as - if not worse than - Tuesday, the deadliest day in a months-long bushfire crisis.

At least 18 people are now known to have died in one of Australia's most devastating bushfire seasons yet, and there are growing fears the toll could rise dramatically, with officials in Victoria saying 17 people were missing in the state.

Many tourists and residents spent two nights isolated with no electricity or telecommunications, before authorities on Thursday declared some roads safe to use.

NSW Transport Minister Andrew Constance called it the "largest evacuation of people out of the region ever," with a queue of cars stretching along the highway toward Sydney as thousands flee the area.

One driver told AFP it had taken her three hours to travel just 50 kilometers.

NSW Rural Fire Service deputy commissioner Rob Rogers said firefighters would be unable to extinguish or even control the raging blazes.

"The message is we've got so much fire in that area, we have no capacity to contain these fires," he told ABC.

"We just need to make sure that people are not in front of them."

John Steele, 73, who lives outside the south coast town of Merimbula, told AFP some people were "panicking" amid the warnings to evacuate.

"There's so much misinformation on Facebook and on the web," he said.

Steele said the region had been "chaotic" in recent days as fresh produce and fuel supplies ran low, but he and his wife were staying put for now.

"We're happy to see every man and his dog leave town," he said. "We are cautious, we have our bags packed."

The number of homes confirmed destroyed in recent days has topped 400, with that figure expected to rise as firefighters reach communities still isolated by flames.

Two Navy ships arrived in Mallacoota - where people huddled on the foreshore for hours on New Year's Eve as a fire bore down on the remote town - to begin evacuating up to 4,000 people.


Newspaper headline: Visitors flee blazes, heatwave