Australia's diving team said it was "not safe" to travel to Japan as they withdrew from a Tokyo Olympics test event on Friday just three months before the pandemic-postponed Games begin.

The Diving World Cup was set to take place from May 1-6 in the Japanese capital.

But with the Japanese government due to impose new virus states of emergency in Tokyo and three other regions on Friday, Diving Australia said they had concluded it would "not be safe to send our athletes and officials to the World Cup".

-It is our clear position, in light of the current circumstances, that a fair and safe Olympic qualification event is not possible at this time- a statement said.

Japan has seen a comparatively small Covid-19 outbreak, with fewer than 10,000 deaths despite never imposing the strict lockdowns seen in other countries.

But surging cases have prompted fresh restrictions as the country gears up to host the Games, forcing torch relays off public roads in an effort to keep spectators away.

The Olympics test events have faced serious disruption, with several postponed or relocated due to surging infections.