A third person from a coronavirus-stricken cruise ship quarantined off Japan has died, the health ministry said Sunday, as new infections among former passengers emerged.Japan has been criticised in the face of mounting evidence that the quarantine imposed on the Diamond Princess did little to stop the virus spreading.More than 20 foreigners evacuated from the vessel have also tested positive after returning home and on Sunday, authorities admitted a Japanese passenger - allowed to disembark after receiving a clean bill of health - had also tested positive for the virus.A Japanese man in his 80s passed away from pneumonia after being taken off the ship, the health ministry said Sunday.Two elderly passengers died on Thursday after contracting the virus.Nearly 1,000 passengers were allowed to leave the ship this week after testing negative, but there are now serious concerns about their status.Among them was a woman in her 60s, who returned home to Tochigi prefecture north of Tokyo by train after disembarking the ship on Wednesday. She later developed a fever and tested positive on Saturday, a local official told AFP.The news comes as infectious disease experts and local officials have questioned the effectiveness of the quarantine period on the vessel."There has been a judgement that those who disembarked after testing negative had no problem, but it has now become clear that those people can turn positive," Tochigi governor Tomokazu Fukuda told a press conference late Saturday."We call on the government to take additional measures," he said.ALSO READ | South Korea coronavirus cases spike, as Italy and Iran take drastic stepsHealth Minister Katsunobu Kato admitted Saturday 23 passengers were released without being tested for the virus during the quarantine period.On Sunday, Kato said he took the latest case "seriously and will strengthen follow-up of passengers", with daily phone calls from local health officials and by asking them to not make any unnecessary outings or use public transport.Those leaving the ship had already been asked to limit travel and wear a mask in public, raising questions about whether the authorities themselves believed a 14-day on-ship quarantine had indeed prevented the spread of the virus.In addition to those allowed off the boat after testing negative, 100 former passengers who had been in close contact with someone who tested positive for coronavirus have disembarked for quarantine on land.Still left on the ship are some travellers waiting for charter flights home and roughly 1,000 crew -- most of whom were not placed in isolation as they were needed to operate the Diamond Princess.Critics suspect they were inadvertently spreading the virus throughout the vessel, which saw more than 600 cases of the COVID-19 disease.Kato has defended Japan's on-board quarantine, telling a TV programme Saturday there was no medical facility large enough to admit more than 3,000 people at once.But the decision of several foreign governments to evacuate their citizens, and stinging criticism by an infectious diseases specialist who described the quarantine on board as "completely chaotic", have undermined Japan's case.Separately, Japan has confirmed at least 132 cases of infection -- including returnees from the Chinese city of Wuhan, the epicentre of the new virus. In many cases, authorities have not been able to trace how people got infected."As we are seeing cases in which we don't know the infection route, now is an important phase in preventing mass infection," Prime Minister Shinzo Abe told his ministers on Sunday at a meeting to discuss counter-measures against the virus.The government has already urged people to avoid large gatherings, and Tokyo's government has cancelled some large public events over virus fears.'Completely chaotic'Japanese authorities have said they made a decision to disembark passengers who tested negative during the quarantine period as they took measures to prevent spread of the virus - passengers were confined to their cabins, except for brief outings on open deck when they were required to wear gloves and masks and keep their distance from fellow passengers.However, infectious diseases specialist Kentaro Iwata has said the situation on the ship was "completely chaotic" and violated quarantine procedures, in blunt criticism rarely seen in Japanese officialdom.The Kobe University professor later said he had heard from a colleague on board that quarantine procedures had improved, but still recommended that all those disembarking the ship should be monitored for at least 14 days and should avoid contact with others.Since Wednesday, about 970 passengers - who tested negative after the government put the ship under quarantine on February 5 - have disembarked, according to local media.On Saturday, around 100 more passengers who had reportedly been in close contact with infected people on board were allowed to get off.They included the last group of Japanese passengers while some foreign passengers were still waiting on board for their governments to send chartered aircraft.With the latest disembarkation, a 14-day quarantine is expected to start for more than 1 000 crew still on board.Many of them were not placed in isolation as they were needed to keep the ship running - preparing food and delivering meals to cabins.Critics have charged that they were inadvertently spreading the virus throughout the ship, which has seen more than 600 cases of the potentially deadly COVID-19 disease.Kato defended Japan's on-board quarantine, telling a TV programme Saturday there was no medical facility large enough to admit more than 3 000 people at once.