Australian swimmer Mack Horton says “lots” of swimmers are using performance-enhancing drugs and says athletes are frustrated with officials “letting them down” by allowing some of them to compete.

Horton sparked controversy at last month’s World Championships when he refused to stand on the podium alongside Chinese swimmer Sun Yang, who had just beaten him to the 400-metre freestyle gold.

After taking the strong stand Horton, was blindsided by the news that his teammate Shayna Jack had tested positive and gone home from Korea, but he maintains her situation is different.

Horton told Channel Seven’s Sunday Night program that Australian officials immediately removed Jack from competition, making it clear that doping violations would be dealt with appropriately.

The Australian said he had been heartened by the support of other competitors and the crowd, having decided at the last minute to follow through on his decision to not step onto the podium with Yang.

This isn’t a China-Australia thing. This isn’t a China versus the world thing. This is a principle and the way the sport is governed and controlled.’’

Horton said he momentarily wavered, but then stuck with his plan to not step onto the podium.

“Literally the last minute. In the lead up … I was not so happy with how things were going, and I thought, you know, regardless of the place I would do this.

“And I told Gabriele Detti who was actually third ‘You know, I’m thinking of doing this. What do you think?’ And he said, ‘No, no. I don’t want to do that’. Which is fair enough.

“I respect that and then I wasn’t sure if I was going to do it. But I did it at the last minute because I didn’t want to live, you know, with regret, thinking back, maybe I should’ve done that at that moment.

“I wasn’t sure. [It] was tense. It was awkward, no one really knew what to do and then all of a sudden the crowd realised what was going on and started, I guess, applauding and it, I guess, filled me with emotion and I was like, ‘OK, this was the right thing to do’.

On the issue of his former teammate Jack, who is facing a lengthy ban after failing a doping test, Horton said it was disappointing and hard to deal with given his stand.

“Yeah, it was hard. It’s really hard … No one was really sure what to think or feel, I think, at the time and, you know, we still had another finals session ahead of us, of competition,” he said.

“[But] as soon as she returns a positive sample, she’s returned to Australia, at a World Championships. And that gives me, I guess, faith in the Australian system.

“Australians demand clean sport and we won’t let our own athletes get away with it and because we won’t let our own athletes get away with it, we can question and demand more from the rest of the world.”

Asked if he had spoken to Jack, Horton said he wanted to speak to Jack to make sure she was OK, but he would not pre-judge the inquiry into her positive test.