Domestic media said the government was considering tougher measures for Tokyo, Osaka prefecture and neighbouring Hyogo prefecture, as experts warned that mutant strains of the virus were driving new outbreaks and straining health services.
Osaka has reported record infections in recent days, prompting the governor, Hirofumi Yoshimura, to request a third state of emergency since the start of the pandemic.
The governor of Tokyo, Yuriko Koike, planned to issue a similar request this week, local media reported.
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As of Tuesday, Japan had reported a total of 542,000 infections and more than 9,700 deaths since the start of the pandemic.
The arrival of a fourth wave in densely populated parts of Japan has caused alarm among medical experts, and could further frustrate preparations for the Olympics, which are scheduled to open on 23 July.
Tokyo has so far reported more than 130,000 infections and 1,850 deaths. On Wednesday it added 843 cases – up from 591 from the same day last week.
Japan this month put Osaka, Tokyo and eight other prefectures under quasi-states of emergency, with shorter business hours for restaurants and bars and stronger calls for teleworking. But the measures have had little impact on infection rates.
Under the next state of emergency – which would be Japan’s third since April last year – restrictions on opening hours will remain in place, but local authorities could also request the closure of shops, theme parks and other facilities, adding to concerns about the impact the virus is having on the world’s third largest economy.
The total economic loss from a renewed emergency in the three regions would be ¥1.156tn (£7.6bn), the Nomura Research Institute said in a report.
Japan’s authorities do not have the legal powers to impose business closures or force people to stay at home. Instead, it has used subsidies and fines to persuade commercial facilities to fall into line, while urging residents to avoid non-essential outings and companies to allow employees to work remotely.
The prime minister, Yoshihide Suga, who on Wednesday cancelled a trip to India over Covid-19 fears, said he would make a “swift” decision after assessing the situation in Osaka and Hyogo, home to the port city of Kobe.
Koike is expected to ask that a state of emergency be declared in Tokyo from 29 April to 9 May, a period that coincides with the Golden Week public holidays, the Mainichi Shimbun reported.
Jiji Press said another region – Kyoto prefecture – was considering requesting similar measures. An emergency declaration covering the four prefectures would cover almost a quarter of Japan’s population of 126 million.
Suga has said new emergency measures would not affect plans to hold the Tokyo Olympics. Opinion polls show a large majority of the Japanese public opposes holding the Games this summer, due to fears they could trigger a fresh outbreak of Covid-19.
The pandemic has already brought disruption to the torch relay since it started in Fukushima at the end of March.
On Wednesday, a lighting ceremony was held inside an empty park in the city of Matsuyama after local authorities requested it be kept away from public roads. The Osaka leg of the relay was similarly affected earlier this month, while torchbearers will also be forced off public roads on Okinawa prefecture’s biggest island next month.
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