Japan's top medical experts warned that holding the Olympics during the Covid-19 pandemic could increase infections, and said banning all spectators was the least risky option, setting up a possible collision with organisers, Reuters reports.

The report, led by top health adviser Shigeru Omi, was released after Tokyo 2020's organising committee chief told the Sankei newspaper she wanted to allow up to 10,000 spectators at stadiums for the global sport extravaganza, which kicks off on July 23.

“This event is different from ordinary sports events in scale and social interest and because it overlaps with summer vacations [...] there is a risk the movement of people and opportunities to interact during the Olympics will spread infections and strain the medical system,” the experts said.

“Holding with Games without spectators is the least risky option and we think desirable.”