More than a week after the Diamond Princess cruise ship was quarantined in Yokohama, the exact scale of the coronavirus epidemic among the remaining 3,600 passengers and crew is unclear.

Within the Japanese government, debate continues over whether to put valuable resources toward screening everyone on board the ship, diminishing its ability to deal with future outbreaks.

The number of people from the ship confirmed to be infected with the potentially deadly coronavirus nearly doubled on Monday to 135. While they are being treated at medical facilities, most others have yet to even be tested, meaning the actual number of infected could be much higher.

Being trapped in cramped quarters is also taking a toll on the elderly who require medical care for conditions unrelated to the coronavirus.

While the solution may seem obvious -- screen the remaining people and let those who are negative disembark -- it is not so clear cut.

Health minister Katsunobu Kato said Monday his ministry is considering screening everyone aboard, but a government official said there is only a limited number of test kits to go around.

"We would be overrun," the official said.

Chief Cabinet Secretary Yoshihide Suga was similarly cautious, telling reporters that "as it stands, it would be difficult."

Related coverage:

2 more Japanese evacuees from Wuhan infected with coronavirus: gov't

New coronavirus death toll tops 1,000 in China

Japan to let elderly off quarantined cruise ship soon: source

The Diamond Princess has remained in Yokohama Port near Tokyo since Feb. 3 after a man who disembarked in Hong Kong was discovered to be infected with the coronavirus. The quarantine will not be lifted until Feb. 19 at the earliest.

The government has conducted a total of 439 tests as of Monday, initially prioritizing those with symptoms such as coughing and high fever and others who had been in close contact with such people, and later including the elderly and those with pre-existing conditions.

Experts are split on whether everyone aboard should be screened for the coronavirus.

Yoshiaki Katsuda, a professor at Kansai University of Social Welfare, said no. "It would use up a lot of test kits, meaning if another outbreak happens in Japan we may not be able to deal with it swiftly."

Hiroyuki Kunishima, a professor at St. Marianna University School of Medicine, said it will ultimately be decision for politicians to make.

"We still don't know much about this virus, including how contagious it is. Considering how anxious the passengers must be, politically speaking it will probably become necessary to test everyone," he said.

The situation is further complicated by the fact that many on the ship are elderly. According to the Ministry of Health, Labor and Welfare, 2,144 or around 80 percent of the passengers are above 60, with 215 in their 80s and 11 in their 90s.

A man on the ship who spoke to Kyodo News on Monday complained that there are not enough doctors and nurses to tend to those feeling unwell, and that an onboard hotline for medical inquiries is always busy.

The government over the weekend delivered some 750 doses of medicine to treat common conditions such as diabetes and high blood pressure, but other treatments readily available in pharmacies, such as fever-reducing medicine, sometimes do not arrive for several days, the man said.

Masahiro Kami, head of the Tokyo-based nonprofit organization Medical Governance Research Institute, warned that the stress of being trapped indoors for days on end could have a dangerous effect on elderly people with pre-existing conditions.

"It will make them more vulnerable to the coronavirus, which could be life-threatening."