About 3700 people on Carnival's Diamond Princess face at least two weeks quarantine on the ship, which has 20 virus cases, including two Australians, and testing continues. Japan now has 40 virus cases.

In Hong Kong, a cruise ship with about 3600 passengers and crew was quarantined for a second day on Thursday pending testing after three positive cases onboard.

Authorities said 33 crew members on the World Dream had developed respiratory tract infection symptoms and three had been sent to a hospital for isolation and management after developing fevers.

All but one of the 33 tested negative for the disease, with the remaining test pending, the city's health department said.

Taiwan's health authority banned all international cruise ships from docking at the island from Thursday.

Another hotspot emerged with at least three people contracting the disease after attending a mid-January company meeting held with 94 overseas staff, including one from Wuhan, at the Grand Hyatt hotel in Singapore.

The case provided more evidence the virus is spreading through human-to-human contact outside China.

The virus death toll in mainland China jumped by 73 to 563 on Thursday, its third consecutive record daily rise, as experts intensified efforts to find a vaccine for a disease that has closed Chinese cities and factories and could damage the world's second-largest economy.

Hubei province, the epicentre of the epidemic, reported 70 new deaths on Wednesday and 2987 new confirmed cases - more than 80 per cent of the total reported by Chinese authorities.

The other fatalities were in Tianjin city, the northeastern province of Heilongjiang and Guizhou in the southwest.

Hubei has been in virtual lockdown for nearly two weeks, with train stations and airports shut and roads closed.

The flu-like virus was first identified in Hubei's capital, Wuhan, and is believed to have originated at a seafood market.

There have been two deaths outside mainland China - in the Philippines and Hong Kong - both involving people who had been to Wuhan, where more than 400 people have died.

Nearly 260 cases have been reported in 31 other countries and regions outside mainland China, according to a Reuters tally.

Hundreds of foreigners have been taken from Wuhan and placed in quarantine centres around the world.

Another 350 American evacuees from Wuhan were placed under quarantine at two military bases in California, bringing to nearly 400 the number of people subject to the US Centers for Disease Control and Prevention's first public health quarantine in 50 years.

More than two dozen airlines have suspended or restricted flights to China and several countries have banned entry to anyone who has been in China in recent weeks.

Hong Kong said all visitors from mainland China would be quarantined for two weeks, while Taiwan extended a ban on entry to foreigners who had been to mainland China in the past 14 days to include those from Hong Kong and Macau.

WHO said experts would gather in Geneva on February 11-12 to try to find a way to speed research into drugs and vaccines. A multinational WHO-led team would go to China "very soon".

China's National Health Commission said another 3694 coronavirus cases were reported throughout the country on February 5, bringing the total to 28,018.

While most people infected with the virus recover quickly with only mild symptoms, it can lead to pneumonia and other severe respiratory illnesses.

Australian Associated Press