The death toll from the coronavirus has risen dramatically as New South Wales authorities are expected to shortly confirm Australia's fifth case the illness.

China has announced at least 80 deaths in the country so far, with more than 2700 people infected by the virus.

China's health minister said the country was entering a "crucial stage" as "it seems like the ability of the virus to spread is getting stronger."

NSW Health on late Sunday said a patient had preliminarily tested positive to the virus and was undergoing further examination.

Authorities were seeking to track down people who have been in recent close contact with the person.

Three men aged 35, 43, and 53 are being treated in a Sydney hospital for coronavirus but are listed as stable, and NSW Health Minister Brad Hazzard on said he was pleased with their progress.

Authorities have spoken to all but two people who have been in close contact with the three men since they arrived from China.

In Victoria, a man in his 50s is being treated at Monash Medical Centre, while four of his family members are being quarantined at home.

The Chinese government also reported five cases in Hong Kong and two in Macao. Small numbers of cases have been found in Thailand, Taiwan Japan, South Korea, the US, Vietnam, Singapore, Malaysia, Nepal and France.

Australian chief medical officer Brendan Murphy said he had sent a letter to every GP in Australia, asking them to consider any recent arrival from Wuhan with flu-like symptoms a potential coronavirus case.

"They will probably turn out to be negative, but they should be treated that way, isolated and then referred to the nearest emergency department with calling ahead," Dr Murphy told the ABC on Monday.

China's National Health Commission said the incubation period for the virus could range from one-to-14 days, during which infection can occur.

Coronavirus death toll rises dramatically as countries evacuate from China_1
Inset: A new hospital is being built in Wuhan to accommodate the rise in infections. Photo: Getty

Despite the worsening situation, Mr Hunt said the government would not yet suspend flights from China, nor screen every passenger on board.

"Every flight is being met by officials, and officials I'm advised, will be boarding the flights and ensuring each individual who has travelled on those flights is directly receiving information," he told the ABC.

Foreign Affairs Minister Marise Payne said closing Australia's borders due to coronavirus "would be a very significant step".
Australian evacuations

Meanwhile, more than 100 Australians, many of them children aged between six months and 16 years, are in lockdown in the Chinese city of Wuhan – the epicentre of the coronavirus outbreak.

"We're working to make sure there's support for those (100) Australians and we are also working, as are other countries, to secure their ability to return," Mr Hunt said.

The Department of Foreign Affairs and Trade is working closely with Chinese authorities to bring the children home, foreign Minister Marise Payne said in a statement to the ABC.

It needs to be established how Australians would be evacuated and whether they need to be quarantined upon their return, Ms Payne said.

"We don't have a definitive number on the number of Australians in Wuhan or in Hubei province because it will include a significant number of dual nationals, some of whom may not have travelled on Australian passports, they've travelled on Chinese passports for example," she told 3AW on Monday.

A notice from the US Embassy in Beijing said there would be limited capacity to transport US citizens on a Tuesday flight from Wuhan that will proceed directly to San Francisco. It said that in the event there are not enough seats, priority will be given to to individuals "at greater risk from coronavirus."

The French Consulate also was considering an evacuation of its nationals from the city. It said it's working on arranging a bus service to help French citizens leave Wuhan.

Japan was also making preparations to fly its nationals out of Wuhan.Chinese travel agencies have been told to halt all group tours, and concern is growing over the potential impact of millions of people travelling back to the cities after the Lunar New Year holiday ends on Thursday.

The spread of the coronavirus comes amid China's busiest travel period of the year, when millions crisscross the country or head abroad for the Lunar New Year holiday.

-with AAP