Chalmers announced himself on the global stage by winning gold in the 100m freestyle at Rio 2016, becoming Australia's youngest swimming Olympic champion since Ian Thorpe at Sydney 2000.

Like athletes across the world, 21-year-old Chalmers was training hard for Tokyo 2020 when the coronavirus pandemic put sporting dreams into sharp perspective.

"It would have been wrong of us as Olympians or the Olympic Games to put ourselves ahead of health," he told AAP.

"When they made the announcement that it was going to be postponed for a year it was a relief more than anything.

"It's such a massive thing going on in the world it would have been wrong of us to just go ahead and think everything was going to be OK.

"We need to band together and fight this virus."

For Adelaide-based Chalmers, the last four years has revolved around training "to go fast in July", but he is now looking forward to facing the world's leading swimmers in 15 months' time.

"I'm really excited for that opportunity," he said. "I've tried to look at all the positives. I'm going to be 22 turning 23 next year - a year further into my prime years as a swimmer.

"I've had a couple of weeks off and am now doing this broken training (because of the restrictions of social distancing). I know that when I get back in the pool I'm going to be hungrier than ever.

"(The delay is) going to benefit me more than anything."

One side-product of the 12-month delay for the Tokyo Games is the shorter turnaround between Olympiads, with Paris 2024 scheduled less than 36 months after competition finishes in Japan.

"One of the good things is that after this one it means there is only three years until the next Olympics, so that's something else to look forward to," he said.

Along with Canada, the Australian Olympic Committee (AOC) was among the forerunners in calling for the postponement of the Tokyo Games, indicating in March that it would refuse to send athletes to any competition taking place in the current pandemic.

"I went in and swam 4km after finding out that the Olympics wouldn't be happening, which was quite a challenge," Chalmers said.

"But I realised that was going to be my last swimming for a while so I really took advantage of every lap and had fun doing it with my squad.

"It was a weird feeling not knowing how long it would be before we would next swim as a squad, or would be back in a 50-metre pool.

"But I completely understood the AOC making that decision and was completely behind it.

"They definitely made the right decision, and it helped the IOC (International Olympic Committee) make the right decision too."

Australian Associated Press