Already in effect in three regions, the measures, set to run from Friday until February 13, are expected to be approved by the prime minister after getting the sign-off from an expert panel.

The quasi-emergency measures, as they are called, permit governors to limit mobility and business activities, by shortening the operating hours of bars and restaurants, and barring sales of alcohol.

"While the measures won't be as effective as when numbers were smaller, I think they still can mitigate things," said Gautam Deshpande, a doctor at St. Luke's International Hospital in Tokyo.

"The horse is only half out of the barn at the moment."

Japan added more than 32,000 new COVID-19 infections on Tuesday, a tally by national broadcaster NHK showed, exceeding an August high soon after Tokyo hosted the Summer Olympics.

New cases hit a record of 5,396 in the western prefecture of Osaka, while the Kyodo news agency said Tokyo's daily infections will reach a record of 7,000 on Wednesday.

Although Omicron is more infectious than previous variants it appears to cause less serious illness, but public health experts still worry that a wave of such cases could overwhelm the healthcare system.

Japan has declared states of emergency four times during the pandemic, and vaccinated about 80 per cent of its population of 126 million, although its booster dose program has reached just 1.2 per cent.

Authorities have "dragged their feet with boosters," Deshpande added.

Japan rolled out quasi-emergency curbs this month in three regions hosting US military facilities, after it appeared that base outbreaks of Omicron spilled into surrounding communities.

Tokyo's occupancy rate of hospital beds for COVID-19 patients, a figure closely monitored by authorities, rose to 23.4 per cent on Tuesday. An increase to 50 per cent would warrant escalation to a full state of emergency, officials have said.

Australian Associated Press