"We've requested through the foreign ministry the list of passengers who boarded the cruise ship but have not received the list yet for various reasons," Vice Health Minister Kim Gang lip said in a press briefing in response to a question about the list.

Japan began to allow passengers of the Diamond Princess moored in Yokohama to leave the ship on Wednesday if they tested negative for the virus. The cruise ship had been in quarantine since it reported the first group of virus infections early this month.

The number of confirmed cases has swelled to more than 620 out of some 3,700 aboard.

A foreign ministry official later cited legal matters as a reason for the difficulties in receiving the list, adding that the government has been asking local airlines and passenger ship firms to do their own checks.

"We have been asking passenger ship companies and airlines to confirm, as passport stamps would show the arrival date. If it was Yokohama, the date would be there and each company can decide whether to issue a ticket," the official told reporters.

South Korea has decided to bar non Koreans who had been on the ship from entering the country and asked Japan for a passenger list.

A total of 14 South Koreans were aboard the ship. Six of them, as well as the Japanese spouse of one, were brought back to South Korea on a presidential plane earlier this week and put under quarantine at a facility near Incheon International Airport. All of them tested negative for the virus, Kim said.

The other South Korean passengers will go into self quarantine at their homes if they return to Korea, officials said.

Amid growing fears over community spread, particularly in provincial regions, Seoul has been stepping up quarantine efforts. South Korea added 31 more confirmed cases early Thursday, bringing the total number of infections to 82.

Source: Yonhap News Agency