A group of Japanese health ministry officials partied at a restaurant in Tokyo until around midnight while the metropolitan government's request was in place for eateries to shorten business hours to curb the spread of the coronavirus, a ministry official revealed Monday.

The alleged "farewell" dinner party on March 24 was attended by 23 employees from the Health and Welfare Bureau for the Elderly. Division chiefs were also present at the party held in the capital's glitzy Ginza district, according to the official who expressed remorse for the event.

The Ministry of Health, Labor and Welfare is expected to penalize those in attendance after verifying the facts, with health minister Norihisa Tamura likely to announce an investigation into the matter at a press conference Tuesday.

Although the state of emergency for the virus was lifted on March 21, Tokyo has requested restaurants to shorten their hours of operation by closing by 9 p.m., effective until April 21.

Meanwhile, a proposal made by the government's coronavirus task force recommends limiting dining to a maximum of four people from a close circle, such as colleagues from work.