NSW’s chief health officer, Kerry Chant, said five cases referred to Health NSW turned out to be other illnesses but one remained under investigation.
“That number may change. What is most important is confirmed cases,” she said.
Dr Murphy said laboratories around the country were “sequencing” the disease in a bid to speed up diagnosis. “We will have a specific one-step test,” he said.
He said Chinese authorities were preparing to cut off Wuhan completely. On Thursday, they took the unprecedented step of issuing a midnight order to ban all travel out of the city, which has a population twice the size of Sydney or Melbourne. They have yet to officially ban people from travelling to the city.
Residents have been told by China’s National Health Commission to avoid crowds and public gatherings during Lunar New Year, the busiest holiday travel period in the Chinese calendar.
Prime Minister Scott Morrison warned travellers not to go to the area as the last flight from Australia to Wuhan took off from Sydney at 1pm on Thursday.
Eungyeong Go, a 23-year-old Korean woman travelling on the China Eastern Airlines flight, said she was nervous and had her mask ready. She said she was stopping over in Wuhan on her way to South Korea. “I’m just a bit scared,” she said.
Mr Morrison said the situation was “rapidly evolving” and urged Australians not to be too concerned. “There are over 10 million protective masks in the national stockpile and there have been no confirmed cases [in Australia],” he said.
The Department of Foreign Affairs and Trade upgraded its travel advice on Thursday morning, urging Australians to reconsider travel to the area.
Mr Morrison was more blunt. “I wouldn’t be suggesting people travel there. That’s what the travel advice means,” he said.
Chinese authorities have been racing to contain the threat of the virus. The seven-hour grace period between the announcement of the travel ban and the suspension of services at 10am saw a rush on airports, train and bus stations in Wuhan, the largest city in Hubei province, which has a population of 60 million.
Footage inside hospitals, which has not been independently verified, showed wards crowded with people seeking treatment. Masks are now compulsory for staff of state institutions and all local Communist Party members have been ordered to set an example and lead the containment efforts.
The Chinese government has been eager to avoid a repeat of the Severe Acute Respiratory Syndrome (SARS) crisis in 2003, during which officials were accused of a cover-up until it was too late.
“Anyone who deliberately delays and hides the reporting of [virus] cases out of his or her own self-interest will be nailed on the pillar of shame for eternity,” a notice from Beijing’s Central Political and Legal Affairs Commission said.
Like SARS, the Wuhan coronavirus is believed to have emerged from a wet seafood market that sold wild animals. Chinese authorities confirmed this week they believed the virus could spread from human to human.
There are now 571 confirmed cases of the coronavirus, including in Thailand, the United States and South Korea. Those numbers are expected to rise, along with the death count, which stood at 17 on Thursday afternoon.
Dr Murphy said the virus did not appear as severe as SARS, which killed 10 per cent of infected people. “Whilst there is a mortality, it’s likely many of them have been people with existing chronic diseases,” he said.
With Eilidh Mellis
Eryk Bagshaw is an economics correspondent for The Sydney Morning Herald and The Age, based at Parliament House in Canberra