SYDNEY (AFP) - Australia's elite swimmers should now be in peak condition and eyeing Olympic medals but instead, like their rivals from other countries, they are treading water - and wondering whether they will get to compete in Tokyo at all.

The decision to postpone the 2020 Games for a year because of the coronavirus was "devastating", team bosses said, with preparations thrown into disarray and mental as well as physical fitness needing careful management.

With the pandemic showing no signs of abating, Japanese and International Olympic Committee officials have spoken openly about cancelling the Games altogether.

Adding to the turmoil for Australian swimmers, long-time coach Jacco Verhaeren quit last month to return to his native Netherlands.

Verhaeren took control in 2013 after Australia's poor results at the London Olympics a year earlier, a campaign marred by ill-discipline, drug use and drunkenness.

He steadied the ship and helped restore Australia as a swimming superpower, with the squad finishing second only to arch-rivals the United States at the 2015 and 2019 world titles.

Swimming Australia has turned to Rohan Taylor, who was state coach for Victoria and Tasmania and has been around the national team for years, as his replacement.

He inherits a squad boasting a slew of world champions including Mack Horton and Ariarne Titmus, along with experienced sisters Cate and Bronte Campbell.

Taylor told AFP in an interview that his immediate focus was to get them through the anguish of the Games being postponed, and deal with the uncertainty of whether they will go ahead.

"Any athlete who is highly competitive across any sport is motivated daily, and what gets them up and moving is that carrot at the end of the stick. And when that was taken away it was quite devastating for them," Taylor said.

"And then of course it is back on, but we still can't really get our hands around it.

"So I think there is a bit of treading water, doing what they can do, keeping themselves under good control and recognising there's still a long way to go."

Australian swimming legend Grant Hackett, who has dealt with his own mental demons including a breakdown in 2017, said being an Olympic athlete right now would be "hugely challenging".

"People put their whole life on hold for the Olympics. You stop studying, you stop doing other things, you stop being a well-rounded person," he told the Sydney Morning Herald.

Hackett added: "The worst thing as an athlete right now is to be in that halfway house. You have to train for it like it's on, believe it's on and commit to that degree; commit like it's happening and if it doesn't happen, so be it."

After about six weeks of being banned from pools due to government coronavirus regulations, most of Australia's top swimmers are now allowed back in the water.

But given continuing travel restrictions, any competition leading into Tokyo is likely to be on home soil. The 2021 world championships have been moved to May 2022 to accommodate the Olympics, and the short course titles rescheduled to December 2021.

Australia is set to hold its national championships in April, with finals in the morning and heats in the evening to mirror what will happen in Japan, ahead of Olympic trials in June.

Taylor, best known for coaching Australian breaststroke queen Leisel Jones, who won seven world titles and nine Olympic medals, said he was heartened by the excellent culture within the team.

Maintaining that is vital to future success, he added, with a leadership group including the Campbell sisters, Mitch Larkin and Jessica Hansen acting as conduit between himself and the squad.

"We really value their feedback and input," he said. "But every athlete on the team, for me, provides leadership - how you go about your business, how you prepare yourself, how you handle yourself throughout the campaign is influential on others."

Swimming is Australia's most prolific Olympic sport, and they have a storied rivalry with the United States.

With that comes pressure, which Taylor is ready to embrace, insisting that "we always want to be better than we have done before, that's always the goal".

After a record Australian haul of 20 swimming medals at the 2008 Beijing Olympics, the team managed only 10 in Rio four years ago, and bettering that is important.

But equal focus is on swimmers' conversion rate - clocking better times at the Olympics than at the trials.

"We've got plenty of time, we just need to do the right things now," Taylor said. "Not over-training, that's helped well-being, they don't need to push themselves."

"If all things go well, we will have a really long run-in, so we'll be pretty confident."