NEW YORK • Cruise company Royal Caribbean said that it had barred all guests holding Chinese, Hong Kong or Macau passports from boarding its ships.

A coronavirus screening had already led Royal Caribbean to delay a cruise ship scheduled to leave New Jersey on Friday.

In its statement announcing the passport rule, the company said it was taking a number of steps to keep passengers safe, including "thoroughly sanitising the cruise ship terminal before and after every sailing" and adding medical staff.

The statement on Friday added: "Any guest or crewmen travelling from, to or through mainland China, Hong Kong or Macau less than 15 days prior to their sailing will be unable to board any of our ships.

"We take this very seriously and have a responsibility to maintain a safe and healthy environment on board our ships."

The vast majority of affected passengers would be on ships leaving China, which account for only 6 per cent of the company's business, according to Mr Rob Zeiger, a spokesman for Royal Caribbean.

Since the outbreak of the coronavirus last month, thousands of passengers on cruise ships have been placed under quarantine.

China has complained bitterly about bans and measures that go against World Health Organisation recommendations, and accused governments and companies that take such actions of fear mongering.

Last Monday, the Japanese government quarantined a ship in Yokohama, the Diamond Princess, with more than 3,700 crew and passengers on board, after learning that a man who had disembarked in Hong Kong on Jan 25 had tested positive for the virus.

Yesterday, the Japanese government said three more people on Diamond Princess had tested positive for the new coronavirus, bringing the number on board to 64, with passengers facing a two-week quarantine.

The three passengers are two Americans - a woman in her 60s and a man in his 70s - and a Chinese woman in her 30s, the ministry said without giving their names. They have already been sent to hospital, it added.

In Hong Kong, the World Dream cruise ship carrying more than 1,800 passengers and an equal number of crew have been quarantined since Feb 5, after passengers from the Chinese mainland who boarded from Jan 19 to 24 tested positive for the coronavirus.

As of yesterday afternoon, 35 staff and nine passengers showed symptoms of fever or respiratory infection, even though all the test results came back negative. The tests will be completed by Tuesday, according to Hong Kong health authorities.

NYTIMES, REUTERS, AGENCE FRANCE-PRESSE, BLOOMBERG