Australia's Mr 'Natural' World goes on anti-HGH crusade.

The first Australian to be crowned the Mr World of natural bodybuilding says sports authorities are in denial if they believe Australia's elite athletes aren't cheating by using human growth hormone.

Ryan Laos, a life-time drug-free bodybuilder, says the expensive HGH, which is available by prescription as an anti-ageing drug - and which actor Sylvester Stallone was caught with at Sydney airport in 2007 - is easily obtainable on the black market and believes claims that it doesn't enhance performance in rugby league are ''a load of rubbish''.

''It would be totally stupid to think that there aren't people in elite sports who have been using HGH for many years,'' Laos said.

AFL last week became the first Australian sporting code to implement blood-testing for HGH.

However, rugby league is yet to follow. It is set to become a tricky issue after Wakefield hooker Terry Newton was banned for two years by England's Rugby Football League after testing positive to HGH, the first such result in any code.

The league's executive chairman, Richard Lewis, said England strongly supported blood testing - the only way to identify HGH - in addition to the range of urine-based testing. But the NRL is still deliberating.

''There are plenty of people who say that [HGH] is not a threat for rugby league,'' NRL spokesman John Brady said. ''Some of our advice is that, by nature of what it does, [HGH] is going to suit an athlete in AFL more than league because it's more aerobic. There are others who say it can't be taken without steroids and if you take it with steroids you'll test positive anyway.''

Brady said the tests were expensive - about $600 each - and the NRL didn't want to spend a lot on low-risk testing at the expense of higher-risk areas.

The reason HGH is so hard to detect is because growth hormones occur naturally.

''So if you find it in a sample the person can say it's just natural,'' said an endocrinologist, associate professor Tony O'Sullivan, from the University of NSW's St George Clinical School.

Hard to detect, but not hard to buy. Laos said that finding hormones was no harder than finding illicit drugs.

''It's available all over the place,'' he said. ''You can ask in a pub and you'll probably get someone carrying steroids or HGH, just like they might have cocaine or ecstasy.''

And it's no cheaper. Laos said the people he knew who use HGH spent about 10 times as much as they would on anabolic steroids, precluding many bodybuilders from using it.

''In other sports there might be people earning a lot of money and they can afford it and they can get away with it,'' Laos said.

As in league or, until now, AFL. And the indications are interesting.

''There's some footy players who will say they've put on eight or 10 kilos in the off-season,'' Laos said. ''You think to yourself, 'Bloody hell, how did you do that?'

''Then you see them with their shirt off and they're lean. They haven't put on fat. I don't want to accuse anyone but for an intermediate or advanced trainer, you can only gain up to three kilos of lean muscle per year. A beginner might put on 10 kilos quickly, but not someone who's been training for a while.''

Richard Ings, chief executive of Australian Sports Anti-Doping Authority, said the authority had the ability under legislation to test athletes any time anywhere, as a urine test or blood test, and did not need permission from the sport.

''When AFL says they've agreed to testing for these substances, it means that they've agreed to fund it,'' he said. ''What kind of tests the rugby league chooses to fund or not is entirely up to them. It's a difficult drug to test for.''

Another big problem with HGH testing is that it clears the body within a day or two; if testers are going to catch a cheat they need to have intelligence about when the drug is being used so they can catch the person in time.

On Thursday, the authority announced a two-year ban on 2008 International Sport Kickboxing Association welterweight world champion Andrew Keogh for possession and use of HGH. In December 2008, Queensland Police found Keogh in possession of HGH. He pleaded guilty to possessing dangerous drugs on January 21, 2009.

University of New South Wales associate professor Tony O'Sullivan was trying to study the effects of human growth hormone when he fell victim to the drug's black market.

The steroid hormones expert was set to commence a study into growth hormones 15 years ago but the supply never arrived.

"It was only a small amount and it doesn't necessarily mean that it was stolen for use by sportsmen, it could have been used by bodybuilders or whatever,'' O'Sullivan said. ''But I suspect it was stolen by someone who wanted to sell it on the market. That's what happens" he said.