GWANGJU, South Korea — Britain's Adam Peaty has said a new rule aimed at preventing a repeat of the podium protests that have shook up the world championships in Gwangju will not stop him speaking out on issues such as doping, The Times reported on Thursday.

Swimming's governing body FINA sent warning letters to Australia's Mack Horton, Briton Duncan Scott and China's Sun Yang after incidents at medal ceremonies in South Korea this week.

Horton refused to share the podium with Sun, who served a doping suspension in 2014 and has another case pending at the Court of Arbitration for Sport, while Scott blanked the Chinese swimmer on the podium.

The Times said FINA had added a clause to its code of conduct for that calls on swimmers to "strictly avoid any offensive or improper behavior towards the officials, the other competitors, the team members and/or spectators during the entire conduct of the competition".

Olympic breaststroke champion Peaty, who has been highly critical of Sun and FINA over the doping issue, said the changes were "meaningless" and that swimmers needed representation.

"We’re here to swim and we’re not going to get involved in a (discussion on a) code of conduct that ain’t gonna change anything," he was quoted as saying.

"Athletes are always entitled to freedom of speech and when we detect that something is wrong and there's cheating, then why shouldn’t we have a voice?"

Peaty, who completed a third straight 50-100m breaststroke double at the world championships, added: "Any doping in the sport is a straight no from me."

Horton, who called Sun a "drug cheat" at the Rio Olympics before beating him to gold in the 400 meters freestyle, has received death threats on social media over his latest protest.

Horton and Scott have received plenty of support at the world championships however, with fellow swimmers praising them for taking a stand.

"You know they’re truly the most courageous guys and I couldn’t be more proud of both of them," said Australia's Mitch Larkin on Wednesday.

"They're standing for what they believe in and that’s clean sport and if we didn’t believe that we wouldn’t be racing here today." — Reuters