A semi-state of emergency will be extended to Tokyo and two other prefectures amid fears of the rapid spread of new variants of the coronavirus, Japanese Prime Minister Yoshihide Suga says.
Tokyo, which will host the Olympic Games in less than four months, confirmed 537 new infections on Friday, exceeding 500 new daily cases for the third straight day.
The reasons behind the surge are more contagious variants of the original virus and the flow of people, which grew as Japan's new fiscal year started on April 1, Economic Revitalisation Minister Yasutoshi Nishimura said at a government meeting with experts.
Nishimura is in charge of the government's coronavirus response team.
Japan adopted the measure in Osaka, Miyagi and Hyogo prefectures earlier this week. It will come into effect in Tokyo, Kyoto and Okinawa on Monday and last for a month in the capital and until May 5 in the other prefectures.
New variants accounted for about 70 per cent of the infections in Osaka and Hyogo and about 20 per cent in Tokyo, Suga said.
Under the semi-state of emergency, bars and restaurants are asked to close by 8pm and attendance at large events is limited to 5000 people. These rules would be tightened further under a full state of emergency.
If the situation does not change for the better, the government "should certainly consider issuing another state of emergency," Shigeru Omi, who chairs the government's coronavirus advisory panel, told a lower house committee.
Friday's decision comes just three weeks after the government lifted a state of emergency in Tokyo and its neighbouring three prefectures which had been imposed in early January.
The roll-out of Covid-19 vaccines has been extremely slow since its launch in mid-February. Only 0.3 per cent of the population has been fully vaccinated, according to the Ministry of Health, Labour and Welfare.
The western prefecture of Osaka declared a state of medical emergency on Wednesday as hospitals were overwhelmed by the pandemic.
Osaka reported 883 new cases on Friday a day after marking its record daily figure of 905.
The spike forced Osaka Governor Hirofumi Yoshimura to cancel the Olympic torch relay in the entire prefecture scheduled next week.