Japan aims to start vaccinating the general public against the coronavirus in May -- just two months before the postponed Olympics -- following targeted jabs for the most vulnerable, reports said Wednesday.
The Yomiuri Shimbun newspaper said the government is hoping the majority of adults will be vaccinated by July, when the Games are due to open.
The country has agreed with pharmaceutical firms to receive enough doses for all 126 million residents and is working to approve the Pfizer jab as the first to be used in Japan from next month.
Around 10,000 medical workers will be first in line for free inoculation, top government officials have said, followed by 50 million at-risk people including all over-65s.
Ministers hope to start mass vaccination in May at the earliest, the Yomiuri and Sankei Shimbun newspapers reported, citing unnamed government sources.
When asked about the reports, government spokesman Katsunobu Kato said it was too early to announce a schedule and that "vaccination will begin only after the vaccine is approved".
Experts have also warned that vaccine hesitancy in Japan may cloud its roll-out after just 60 percent of Japanese respondents in an international survey published in December said they want the vaccine.
Prime Minister Yoshihide Suga has said he will be among the first to be vaccinated, in an apparent attempt to bolster confidence about the jab.
Tokyo 2020's opening ceremony is in six months, but a surge in Covid-19 infections in Japan and worldwide has cast fresh doubt over the event.
Public support for the Olympics has plummeted, with more than 80 percent of people recently polled in Japan saying the event should be cancelled or postponed again.
But Olympic and Japanese officials insist the Games will go ahead this year with virus countermeasures.
Tokyo 2020 CEO Toshiro Muto told AFP that Olympics organisers are "unwavering" on holding the event this year but can't rule out staging it without spectators.
On Wednesday, the mayor of Osaka called for a second postponement -- a scenario organisers have previously dismissed.
Ichiro Matsui, mayor of the western city of 2.7 million people, said Japan should try to hold the event in 2024 instead.
"Can everyone in Japan be vaccinated by this summer? It is impossible physically," he told reporters. "Japan as a nation state should negotiate with the IOC."
British rower and Olympic gold medallist Matthew Pinsent has also called for Tokyo to host the Games in 2024, with Paris taking over in 2028 and Los Angeles moving back to 2032.