Chinese health authorities said there were 7,711 confirmed cases in the country as of 29 January.

Infections have also spread to at least 15 other countries.

The World Health Organization (WHO) will meet on Thursday to again consider whether the virus constitutes a global health emergency.

“In the last few days the progress of the virus, especially in some countries, especially human-to-human transmission, worries us,” WHO Director-General Tedros Adhanom Ghebreyesus said on Wednesday.

He named Germany, Vietnam and Japan, where there have been cases of people catching the virus from others who have been to China.

“Although the numbers outside China are still relatively small, they hold the potential for a much larger outbreak,” the WHO chief said.

More people have now been infected in China than during the Sars outbreak in the early 2000s, but the death toll remains far lower. Sars, also a coronavirus, caused acute respiratory illness.

Voluntary evacuations of hundreds of foreign nationals from Wuhan are under way to help people who want to leave the closed-off city and return to their countries.

The UK, Australia, South Korea, Singapore and New Zealand are expected to quarantine all evacuees for two weeks to monitor them for symptoms and avoid any contagion.

Australia plans to quarantine its evacuees on Christmas Island, 2,000km (1,200 miles) from the mainland in a detention centre that has been used to house asylum seekers.

Singapore is setting up a quarantine facility on Pulau Ubin, an island north-east of the city-state’s mainland.