Olympic 50 metres freestyle champion Gary Hall Jr. believes the recent glut of world records has more to do with doping than swmisuits.

Since the introduction of the Speedo LZR Racer this year, swimmers wearing the revolutionary bodysuit have smashed numerous world marks.

American Hall, however, believes that the serious doping which once almost destroyed the sport continues to lurk just below the surface.

"I don't have any proof but it's my gut feeling doping exists," Hall said on the opening day of the U.S. trials. "I need to wait and see what it feels to be shaved and tapered in these new technology suits.

"I am convinced there is an advantage to wearing the suits but I don't think it accounts for all the time drops we've seen.

"Do I think it (doping) is getting worse? Yes, I do.

"It's here, it's in the United States.

"I train with an international group of swimmers and all of them have stories and a few of them have had offers and I'm not at liberty to say (any more).

"Unfortunately, we rely on inadequate (anti) doping agencies for proof."

The flamboyant and outspoken Hall, who once threatened to smash a rival Australian relay team like a guitar, arrived at the Olympic trials in a private jet.

On the day Michael Phelps launched his bid to emulate Mark Spitz's record of seven gold medals at a single Olympics, Hall was back in the spotlight, accusing officials of not doing enough to rid the sport of performance-enhancing drugs.

The 33-year-old is trying to earn a spot in his fourth Olympic team and become the first male swimmer to win the same individual event, the 50 metres freestyle, three times.

"I have no idea where the sport is as a whole but to think it doesn't exist is foolish," he said.

"It drives me crazy and I just don't know how to fight it.

"What bothers me most is the resignation and the attitude of the public that it is just part of sport today. We need to get over that because it is not OK."

Hall has also won three Olympic gold medals in relay events.

Reuters