The spread of the Wuhan coronavirus aboard a cruiseship quarantined in Yokohama has continued unabated as Carnival Corp subsidiary Princess Cruises confirmed another 66 cases of infection on Monday.

Taking into account the eight cases confirmed over the weekend, the total number of patients found on board since the ship was first quarantined by Japanese health authorities on 3 February has climbed to 135.

Newly diagnosed patients are immediately removed from the ship and transferred to medical facilities ashore.

At least 10 other passengers have disembarked due to other non-coronavirus medical needs.

Passengers and crew still on board the Diamond Princess will remain in quarantine until 19 February at the earliest, Japanese authorities say.

Passengers have been largely confined to their cabins during the quarantine period.

Princess president Jan Swartz said over the weekend that all passengers would receive a full refund for their cruise, and a credit for a future cruise for the same amount that they had paid for their current holiday.

Princess is also providing anyone experiencing mental stress or difficulty with access to counsellors via telephone.

“Our guests and crew on board Diamond Princess are the focus of our entire global organisation right now and all of our hearts are with each of them,” Swartz said in a statement released via YouTube on Saturday.

The Diamond Princess was quarantined upon arrival in Japan from Hong Kong after a passenger on the ship's previous voyage had tested positive for the coronavirus several days after disembarking the ship.

The coronavirus outbreak, which began in the Chinese city of Wuhan towards the end of December, has had a catastrophic effect on the Asian cruise sector, with all sailings from China suspended and many ports in the region, including Taiwan, Hong Kong, the Philippines and Japan, closing their ports to cruiseships.

As a result, 11 large cruiseships are currently out of work.

Two other vessels directly affected by the coronavirus saw an improvement in their predicaments over the weekend.

TradeWinds reported earlier on Monday that the quarantine order imposed by Hong Kong authorities on Genting Cruise Lines subsidiary Dream Cruises’ 150,000-gt World Dream (built 2017) was lifted on Sunday after its passengers and crew were given the all-clear following extensive medical testing.

Holland America Line’s 82,900-gt Westerdam (built 2004), which has been sailing aimlessly in the northern Pacific for much of the past week after being denied entry to ports in Japan, Taiwan and the island of Guam, could soon find a port of refuge to disembark its 1,455 passengers.

Holland America revealed on Sunday that it had received conditional preliminary clearance for Westerdam passengers to disembark from two different ports. But the company did not name those destinations.

“We are currently working through all the various required logistical support in both ports to determine the best course of action for our guests,” the company said.

Holland America stressed that there had been no suspected coronavirus cases on board the Westerdam, and all passengers and crew were in good health.

Holland America will provide all passengers with a full refund and a 100% credit for a future cruise.