According to government officials quoted by Kyodo late on Wednesday, Japan has begun looking into the possibility of making sure its Olympic and Paralympic athletes are all vaccinated by the end of June.
Japan rallies to support Osaka after French Open withdrawal.
Japan is currently preparing to extend a state of emergency across much of the nation
The government's top spokesman Katsunobu Kato told reporters on Monday he was unaware of any decision on the issue.
Top Japanese officials said on Tuesday they did not expect a US advisory against travel to Japan amid worries about the coronavirus to affect the Tokyo Olympics - less than two months away - and that US support for the Games is unchanged.
Japanese chief cabinet secretary Katsunobu Kato declined to give details but said Japan would make every effort to protect the Games from possible hacking attempts.
Organisers warn participants against eating out over COVID-19 risks.
Organisers have already banned overseas spectators and set a cap on domestic spectators at 50 per cent of capacity
Another downgrade for Tokyo Olympics that have their pomp and public spectacle overshadowed by COVID-19
New infections have spiked ahead of the Olympics, which are set to start in July
Japan's Mima Ito took the bronze medal after beating Han Ying of Germany in straight games.
As Japan expands state of emergency, calls grow to cancel Games. Japan has repeatedly insisted it will hold the Games despite opinion polls showing a majority of respondents want them postponed again or cancelled.