Osaka Gov. Hirofumi Yoshimura said Monday he plans to request the central government to designate the western Japan prefecture as an area requiring stronger anti-virus measures based on a law, saying it has already entered the "fourth wave" of infections.

Osaka is believed to be the first in the country to seek binding measures against the coronavirus based on a revised law that took effect in February, which include fines for businesses that do not comply with restrictions on operating hours.

Osaka Gov. Hirofumi Yoshimura speaks at Osaka prefectural government office on March 29, 2021. (Kyodo)

"Looking at how fast the virus is spreading, cases will very likely increase this week," Yoshimura said. He indicated the anti-virus measures would include making mask-wearing compulsory for customers at dining establishments.

The central government plans to respect a request from Osaka if it is made, Chief Cabinet Secretary Katsunobu Kato said.

"The prime minister would make the final decision based on infection numbers and the state of the medical system," the top government spokesman told a press conference.

Osaka on Monday confirmed 213 new infections, while Tokyo reported 234. Over the last seven days, new cases in Osaka have totaled 1,933, more than double that of the week prior.

"Osaka lifted its state of emergency (over the virus) earlier (than the Tokyo metropolitan region), so I believe that rebound is also a factor in the high cases," said Yoshimura.

Prime Minister Yoshihide Suga declared a one-month state of emergency in the Tokyo region on Jan. 7, later expanding it to a total of 11 prefectures including Osaka, Aichi, Fukuoka, and extending it for most of them to March 7.

The measure was further prolonged by two weeks to March 21 for Tokyo and three neighboring prefectures -- Chiba, Kanagawa, and Saitama.

Under the revised law, the central government can declare a situation that falls short of a state of emergency but still requires strong measures to combat the spread of the virus in specific areas smaller than an entire prefecture. Yoshimura is set to seek the state designation of this situation.

The western Japan prefecture decided last Friday to extend nonbinding requests for dining establishments in Osaka city to close by 9 p.m. for another three weeks to April 21, and expand the measure to the entire prefecture from Thursday.

Japan on Monday also received the seventh batch of COVID-19 vaccine developed by Pfizer Inc. as the country continues to inoculate health care workers in the first stage of its vaccine rollout.

The shipment of vaccine bottles providing up to 705,510 doses, with six shots available from each bottle, was delivered to Narita airport near Tokyo from the U.S. drugmaker's factory in Belgium.

With the shipment, the amount of vaccine arriving in the country this month has reached some 2.33 million doses. Japan expects supply of about 6.13 million doses in April.

The quantity to be delivered to Japan could increase further in May, given that vaccine production in Europe is on the rise, although the amount depends on export approval from the European Union.

The government plans to complete the delivery to inoculation centers of doses sufficient for two shots for Japan's 4.8 million medical workers in the third week of May. A total of 781,665 workers had received their first shots as of 5 p.m. Friday, according to the health ministry.

Around 36 million people aged 65 and older are expected to get jabs from April 12. They will be followed by people with underlying health conditions such as diabetes and those with psychiatric disorders before the rollout continues for the general population.

The vaccine developed by Pfizer and its German partner BioNTech SE was the first to be approved for use in Japan in February.

Britain's AstraZeneca Plc filed for the approval of its COVID-19 vaccine in early February, followed by U.S. biotechnology company Moderna Inc. earlier this month.

Suga has pledged to secure enough COVID-19 vaccines for Japan's population of 126 million within the first half of 2021.