They also said torch relay staff must test negative for the coronavirus before being sent from Tokyo.

The 121-day torch relay is set to begin on March 25 at the J-Village training centre in Fukushima, launching the build-up towards the July 23 start of the Games, postponed from 2020 because of the pandemic.

"People are fine to watch from the side of the road but when they do so we would like them to practise distancing and avoid crowds," Tokyo 2020 CEO Toshiro Muto told a news conference.

"We want to ensure a safe torch relay not only for the runners, but for the people in the local communities who are kind enough to host it," he said.

Organisers have the unprecedented task of planning the world's biggest multi-sport event during a pandemic. They face tough decisions over whether to allow in overseas fans and how many spectators in general to let into venues.

The "Grand Start" ceremony and first section of the torch relay on day one will not be open to the public as organisers reduce the number of participants and simplify the program.

Underscoring the complications of planning for this year's Games, Japanese soccer player Nahomi Kawasumi said she will not take part in the torch relay after deciding to withdraw from the event last year due to the pandemic.

Kawasumi, who plays for Sky Blue FC in US Women's Professional Soccer, had said just before the Games were postponed last year she was withdrawing due to fears she could contract the virus or infect others.

"Again, I will decline to be a torch relay runner," Kawasumi tweeted on Monday.

"I made this decision because the infectious disease problem has not yet been resolved and I live in the United States", which has the world's highest number of coronavirus cases and deaths.

The Olympics will be held from July 23 to August 8 and the Paralympics from August 24 to September 5.

Australian Associated Press