Photo/IllutrationChina's Sun Yang, centre, holds up his gold medal as silver medalist Australia's Mack Horton, left, stands away from the podium with bronze medalist Italy's Gabriele Detti right, after the men's 400m freestyle final at the World Swimming Championships in Gwangju, South Korea on July 21. (AP Photo)

GWANGJU, South Korea--Mack Horton received a round of applause from fellow swimmers at the world championships after refusing to share the podium with China's Sun Yang, American breaststroker Lily King said on Monday.

Sun, who previously served a doping sanction in 2014 and was labelled a "drug cheat" by Horton before the Rio Olympics final, was given the green light to compete in Gwangju after being cleared by a FINA panel of breaching the governing body's rules earlier this year.

However, the World Anti-Doping Agency is seeking to overturn the decision at the Court of Arbitration for Sport, leaving Sun's career hanging in the balance a year out from the Tokyo Olympics.

After finishing runner-up to Sun in the 400 freestyle on Sunday, Olympic champion Horton took his silver medal and then stood behind the podium while his Chinese rival and bronze medalist Gabriele Detti shared the spotlight.

While the move drew criticism from some quarters of the media, and outrage from Chinese swimming fans, King said the Australian had full support from his peers.

"We were waiting around for the awards ceremony just to see what was going to happen," said King.

"It was awesome. When we walked into the dining hall he walked in after us and the whole dining hall erupted into applause.

"It was pretty good to see the athletes united on his stance and supporting him as well."

King said swimmers were annoyed that doping continues to cast a shadow over their sport, and that if they were not going to receive the proper protection from the governing body they would have to look out for each other.

"I don't think anyone at FINA is going to stand up for the athletes so the athletes have to stand up for themselves," she said. "I think it is definitely a start."

Australia's Mitch Larkin was "super proud" of his team mate and said the whole squad backed him.

"I think 99% of (other) athletes around the pool deck back him, so he's not really standing alone," he added.

"What he did was certainly brave and gutsy and I have a lot of respect for him for doing that."

Larkin said it was difficult to be entirely confident that swimming was clean.

"You've got to trust the authorities but with what's going on in sport these days it's hard to be 100% sure," he said.

American Matt Grevers said that while Horton could be punished by FINA the Australian was well aware of the potential consequences. He also said the protest was aimed more at sending a message to Sun than to damage him.

"In this instance I don't feel like it really hurt Sun Yang. It just let him know that it was a weird incident and until it gets uncovered we don't really trust you," he added.