Japan is vaccinating more than 1 million people a day, but it still lags many major economies in inoculating its population.
Tokyo is already under a state of emergency, the fourth so far in the pandemic, though some experts have said it should be expanded to cover the whole country. The western prefecture of Osaka reported a record 1,654 new cases on Thursday.
Hospital beds are filling up rapidly, mainly with patients in their 40s and 50s, Omi said. To try to break the chain of infection, he said, authorities should try to reduce human mobility to about 50 per cent of the average in July.
His comments echoed those of a separate panel of experts who said on Thursday contagion in Tokyo had become uncontrollable.
“The number of new positive cases is rapidly increasing, making it impossible to control the situation,” Norio Ohmagari, a health adviser to the Tokyo Metropolitan Government, told a panel chaired by Governor Yuriko Koike.
Koike urged residents to avoid travel and stay home to slow the transmission of COVID-19, which is causing hospitals to have to forego some standard medical care.