ELEVEN-time world surfing champion Kelly Slater says recreational drug use in his sport is "rampant".

But the American superstar does not believe drug-testing is the answer, saying addicts have to want to kick the habit and need support.

In an exclusive interview ahead of the season-opening Quiksilver Pro on the Gold Coast, Slater also quashed retirement speculation and vowed to chase a 12th world title at the age of 41.

He opened up about drugs in sport after the Lance Armstrong scandal and claims against some Australian sports.

He said he did not believe surfing had a performance-enhancing drug problem because he did not "think there's a drug you can take to make you surf better".

Asked if there was a recreational drug problem, he said: "There clearly is - absolutely. There's no denying that, it's rampant, it's full-on."

Slater said the Association of Surfing Professionals had introduced drug-testing last year, but it had faltered.

"They tested us at the first event and I never got tested again all year," he said.

"Why talk about it and not do it? Why bother? Either do it or don't do it."

However, Slater said he did not believe drug-testing would help surfers hooked on recreational substances.

He questioned Queensland surf legend Gary "Kong" Elkerton's assertion, in a recently-released biography, that drug-testing might have saved Slater's friend, triple world champion Andy Irons, who died in 2010 after battling substance abuse.

"Those are personal, private matters and it's really hard to dredge them up publicly and come to any kind of conclusion," Slater said.

"Andy was the one who put himself in that situation. Had he had more outside pressure to change, that might have pushed him over the edge more quickly.

"I know a lot of drug addicts and you can't force them to go get help if they don't want it. You just have to show those people love and support and let them know that if they need your help, you're there."

Slater said he would support more stringent drug-testing in surfing.

"I don't think it's necessarily my battle to deal with because I've been drug-free my whole life," he said.

Despite losing the world title to Joel Parkinson in an epic battle in Hawaii in December, Slater said he was motivated to chase a 12th crown.

"I'm going to go for it and try to put together a good year," he said.

"Pretty much every day I get some older dude come up to me and say 'Oh, mate, you've got to keep going'.

"I was one heat away from winning the title last year. I came really close and it wasn't really heartbreaking. I was happy for Parko.

"But right now everyone's got a target on their back we're all starting at zero."