Coronavirus infections in China feared to be more widespread than officially reported, Wuhan in lockdown

China is putting on lockdown a city of 11 million people considered the epicentre of the new coronavirus outbreak that has killed 17 and infected nearly 600 people, as health authorities around the world work to prevent a global pandemic.

The Chinese city of Wuhan, the source of an outbreak of a new flu-like virus, is closing its transport networks and has advised citizens not to leave the city as the death toll rose steeply overnight.

Hospitals in Wuhan are reportedly dealing with huge numbers of sick patients, raising fears the new coronavirus is spreading faster than official reports suggest.

Bus, subway, ferry and long-distance passenger transportation networks will be suspended from 10am (local time), and the airport and train stations will be closed to outgoing passengers, state TV said.

Meanwhile, a flight from Wuhan has arrived in Sydney, where passenger will be subject to additional individual screening by nurses, doctors and biosecurity staff for symptoms of the highly contagious virus.

The Foreign Affairs Department updated their official travel advice for China this morning and warned Australians to reconsider their need to travel to Wuhan, following the outbreak of the deadly virus.

The advice noted new measures put in place by Chinese authorities to try to stop the spread of coronavirus.

It includes advice to wear masks in public places, and avoiding travel in and out of Wuhan.

The Matildas' Olympic qualifiers also have been moved from Wuhan to Nanjing as the city has gone in lockdown.

Wuhan is the most populated city in central China with 11 million people.

There are now 571 cases of novel coronavirus reported across China, with 17 confirmed deaths — almost double that reported a day earlier — according to reports in the country's state media, Xinhua, the China Daily newspaper and Reuters.

The previous report pointed to nine deaths.

Abroad, Thailand has confirmed four cases, while the United States, Singapore, Taiwan, South Korea and Japan have reported one each.

Authorities say they have also confirmed 2,197 cases where people have had close contact with patients.

This comes as the state-owned Global Times newspaper in an editorial appeared to lash authorities in Wuhan for being slow to report the virus had spread to medical workers — a key sign of human-to-human transmission and potential "super-spreaders".

The number of confirmed coronavirus cases includes dozens of people in Beijing, Shanghai, Guangdong province and Zhejiang province, with the majority in central Hubei province, where the city of Wuhan is located.

However, according to messages in a private WeChat group for Chinese medical professionals viewed by the ABC, one hospital in Wuhan has been overwhelmed with patients, with nearly 300 people in that facility alone exhibiting symptoms of the coronavirus.

The information from the group is difficult to independently verify — the ABC made multiple attempts to contact hospitals in Wuhan to ask about the reports, but received no response.

Video footage appeared to back up the reports, showing large lines of patients wearing face masks at a hospital in Wuhan, crowding the wards as doctors moved through checking on them.

Analysis from Imperial College London last week suggested the Wuhan outbreak could have led to more than 1,700 cases, a significantly higher figure than what has been officially reported.

Experts in Hong Kong have suggested the number could be closer to 1,300.

People posting in the group also expressed concern the coronavirus had spread to the city of Nanjing in Jiangsu province.

However, authorities in the city said such statements were "rumours", and no cases had been reported at any of the city's hospitals.

SARS cover-up driving fears

Chinese authorities have been at pains to ensure their response to the outbreak has been as transparent as possible, no doubt in light of the backlash they faced over their handling of the SARS epidemic.

Officials had initially tried to hide the real number of cases of the deadly disease, leading to the sacking of China's then health minister and Beijing's mayor.

The epidemic saw more than 8,000 SARS cases across 37 countries, resulting in 774 deaths.

In a daily press conference on Tuesday, Foreign Ministry spokesperson Geng Shuang said China had been "acting with openness, transparency and a high sense of responsibility towards global health security".

He said China was sharing information on the epidemic with the World Health Organisation (WHO), which held an emergency meeting about the outbreak and its potential global consequences in Geneva on Wednesday evening (local time).

During the meeting the WHO said it would decide on Thursday whether to declare a global emergency over the outbreak of the virus spreading from China.

If it does so it will be only the sixth international emergency to be declared in the last decade.

"The decision is one I take extremely seriously," WHO director-general Tedros Adhanom Ghebreyesus said, adding that he was only prepared to make it with the appropriate amount of consideration and information.

He was speaking after the WHO held a day-long meeting of an independent panel of experts in Geneva on Wednesday.

WHO spokesman Tarik Jasarevic said new cases of the coronavirus would appear as China stepped up monitoring.

The WHO said an animal source appeared most likely to be the primary source of this outbreak.

In Australia, one man in Brisbane was briefly placed in isolation after returning from Wuhan with flu-like symptoms, but subsequently released.

Hong Kong has reported 118 suspected cases, according to the South China Morning Post; however, 88 of those people have since been discharged.

Macau, another special administrative region of China, also announced its first confirmed case of the virus on Wednesday.