Olympic bronze medallist diver Anabelle Smith has slammed global governing body FINA for pressing ahead with a qualifying event for this year's Games in Tokyo despite a spike in COVID-19 cases in the Japanese capital.

Diving Australia pulled out of the May 1-6 World Cup for safety reasons, meaning Smith and her partner Maddison Keeney will not now have the chance to qualify for the Olympics in the synchronised three-metre springboard event.

"To have our team's opportunity to qualify in remaining events removed, due to decisions that oppose one of the very principles of Olympism 'fair play' is truly devastating," Smith wrote in a post on Instagram.

"Maddi and I have been stripped of our chance to defend our Olympic bronze medal, in an event we have pushed the boundaries in since Rio."

The World Cup was scheduled to begin in Tokyo on April 18 but, having considered a change of venue, FINA moved it to the later date after discussions with Games organisers, the Japanese government and the International Olympic Committee.

Japan on Friday declared a state of emergency for Tokyo to run from Sunday to May 11 as the country struggles to contain a resurgent coronavirus pandemic three months before the Olympics.

Keeney echoed her partner's comments in an Instagram post of her own.

"Absolutely disappointed that we have to pull out of the event, but more so disappointed in FINA and their decision to push forth with the World Cup," she wrote.

"The Olympics is about fairness, equality and excellence, all at which are thrown out the window with their decision, given the extreme situation the pandemic has caused around the world."

Australia, the seventh most successful nation in Olympic diving, have already secured seven spots in the diving competition for Tokyo but could have earned five more at the World Cup.

Diving Australia said it was confident the Olympics would be safe for athletes and was continuing discussions with FINA over "qualification flowing from the World Cup".

"FINA has stated a 'fair competition is of utmost importance' and that the World Cup should be a 'safe, secure and fair Olympic qualification event'," it said in the statement announcing the Australian withdrawal from 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."