Japan's health ministry said a woman in her 80s living in Kanagawa prefecture, just to the west of Tokyo, had died. She was transferred between hospitals as her condition worsened and was only confirmed to have the coronavirus after her death.

A Tokyo taxi driver, reportedly the woman's son-in-law, as well as a man in his 20s just east of Tokyo and a doctor in Wakayama, western Japan, were also confirmed to have the virus.

"We will stay in touch with local governments and expand our testing procedures and treatment of patients in order to prevent the spread of the illness," Prime Minister Shinzo Abe told reporters, a day after a task force on the disease drew up new measures to deal with it, including spending 10.3 billion yen from budget reserves.

Planners will also keep in close contact with Japan's military, chief cabinet secretary Yoshihide Suga told a news conference, without giving further details.

He said the number of people confirmed to have the virus in Japan had risen to 33, with another 218 on a cruise ship quarantined at a port in Yokohama.

Separately, some passengers on the cruise ship Diamond Princess, which has been moored at Yokohama, just south of Tokyo, were set to start disembarking on Friday instead of waiting for the originally targeted date of February 19.

Elderly passengers who have medical conditions or are in windowless rooms can complete their quarantine onshore.

The ship was quarantined on arrival in Yokohama, near Tokyo, on February 3 after a man who disembarked in Hong Kong before it travelled to Japan was diagnosed with the virus.

About 80 per cent of the ship's passengers are 60 or older, with 215 in their 80s and 11 in their 90s, according to Japanese media.

Australian Associated Press