Canada has become the first nation to officially withdraw its athletes from the 2020 Olympic games, sparking further doubt over whether the Tokyo games will go ahead as planned.

The Canadian Olympic and Paralympic committee said it had taken "the difficult decision" to withdraw after consulting athletes, sports groups, and the Canadian government.

It comes after the International Olympic Committee gave itself a four week deadline to make a decision on whether or not to postpone the games, which are due to begin in July.

"While we recognize the inherent complexities around a postponement, nothing is more important than the health and safety of our athletes and the world community," a statement from the Canadian Olympic Committee and Canadian Paralympic Committee said on Sunday.

"This is not solely about athlete health -- it is about public health," it added.

Australia's Olympic committee have also said they will be unable to assemble a team for the Tokyo games if they go ahead as planned, saying their country's athletes should begin planning for an Olympics in 2021.

"It's clear the Games can't be held in July," said Ian Chesterman, Australian Team Chef de Mission for Tokyo.

"Our athletes have been magnificent in their positive attitude to training and preparing, but the stress and uncertainty has been extremely challenging for them," he added.

Having previously stood firm on the games going ahead as planned in July, the IOC now appear to have come to the realisation that the games will have to be changed.

The board have insisted that cancelling the games is not on the agenda, but postponement is expected the most likely outcome.

The IOC's executive board met on Sunday amid mounting pressure from athletes and national Olympic committees for the Tokyo Games to be delayed due to the coronavirus outbreak.

A number of governing bodies have called on the games to be rescheduled, however Canada are the first country to officially withdraw.