They also announced athletes will have daily coronavirus tests, increased from an initial plan for tests every four days, as they firm up virus rules in a bid to build support for the postponed 2020 Games.

With less than three months until the opening ceremony, parts of the country including Tokyo are under a state of emergency following several spikes in infections.

Overseas fans have already been barred and organisers had intended to set a domestic attendance limit this month.

But that has now been put back and a decision could come just a month before the opening ceremony on July 23.

"As we look into the evolving situation with the domestic infections status involving new strains, we have agreed that a decision regarding spectator capacity at the Olympic and Paralympic venues will be made in June," Olympic officials said after top-level talks Wednesday.

More details are expected soon on other virus rules for athletes as organisers update their "playbooks" for the Games.

But among those announced after the meeting was the daily test requirement for all athletes "and those in close proximity... to minimise the risk of undetected positive cases".

"We are ready with you to take all the necessary measures to minimise the risks to make the Japanese people feel safe," International Olympic Committee chief Thomas Bach said at the start of the talks.

"Our top priority is health and safety for everyone -- not only for the participants of the Olympic Games but, first and foremost, also of our gracious hosts, the Japanese people."

                  
'People are anxious'       

                  
With the Games looming, Japan faces what some experts have called a fourth wave of the virus.

A new state of emergency was imposed on Tokyo and three other areas on April 25, and the government's top medical advisor warned Wednesday that discussions should start soon on how the Games could be held if infections remain high by the summer.

"What's very important is the situation of the infections and how overwhelmed the medical system is," Shigeru Omi told parliament in response to a question from an opposition lawmaker.

"I think it is time to discuss the Olympics," he added, while stopping short of calling for either a postponement or cancellation.

Polls show most Japanese oppose holding the Games this summer, backing either another delay or scrapping the event altogether.

But Olympic officials insist it can be held safely, with Tokyo 2020 chief Seiko Hashimoto last week saying that organisers are "not thinking about cancellation".

"There are so many people who are looking forward to the Games," she said on Wednesday.

"But, on the other hand, there are a lot of people who are anxious. That's the reality, and we need to look at both sides."

Olympic chiefs took the unprecedented decision to ban overseas fans in March, in a bid to reduce virus risks. 

Domestic ticket sales have not yet resumed after last year's postponement. Organisers said around 4.48 million tickets had been sold in Japan, and nearly a million for the Paralympics.

Tickets purchased by overseas fans are being refunded, and organisers have also