The country's top coronavirus adviser, Shigeru Omi, said Sunday it is time to start considering further shortening the quarantine period for people who have been in close contact with COVID-19 patients.

Omi suggested the time for isolation — currently seven days for ordinary people and five days for essential workers — could be cut down as the omicron variant of the virus is known to have a shorter incubation period.

"I think it's time to start a discussion to make it more flexible," Omi said during an NHK television program.