The Japanese government is planning to allow the elderly and passengers with chronic illnesses to disembark a cruise ship quarantined in Yokohama over coronavirus infection fears soon, a source familiar with the matter said Tuesday.

The government has asked about 3,600 passengers and crew members to stay on board during the two-week isolation period through Feb. 19 in an effort to contain the spread of the pneumonia-causing disease in the country.

But the elderly passengers and those with chronic health problems may leave the cruise ship as early as Tuesday morning, the source said.

The decision has emerged as passengers have apparently been under stress during their prolonged isolation on the ship. As of last Wednesday, about 80 percent of the 2,666 passengers were age 60 or older, with 215 in their 80s and 11 in their 90s.

Masahiro Kami, head of the Medical Governance Research Institute, a nonprofit organization, said that elderly people with chronic illnesses could suffer rapid aggravations of their health conditions due to stress if confined to cramped cabins.

"They will be susceptible to virus infection and risk their lives," Kami said, asserting a need to let them off the ship preferentially.

A male passenger told a Kyodo News, "Full medical care is not reaching us even though there are many people whose health is deteriorating."

"We want (the government) to send more doctors, nurses and consultants," he added.

The man, whose age is unknown, pointed out that there is only one extension number for health consultation on the cruise ship, so it is difficult to connect and involves waiting to receive necessary responses.

Although the government delivered medicines for conditions such as diabetes and high blood pressure for 750 people by Sunday, it has not yet been able to get antifebrile medicine to one passenger who has been suffering a high fever.

The Diamond Princess, the cruise ship operated by U.S. company Princess Cruise Lines Ltd., has been kept in quarantine since a passenger, who disembarked in Hong Kong, was found to be infected with the virus.

As of Monday, 135 people on the ship have tested positive for the coronavirus.