The AFL last night confirmed it had commissioned regular target-testing for human growth hormone (HGH) and the performance- enhancing drug known as EPO on up to 30 players in the past 15 months.

AFL football operations manager Adrian Anderson told The Footy Show that the testing through the Australian Sports Anti-Doping Authority had targeted high achievers in the game and players who had shown particularly sharp improvement.

Some players are understood to have been tested more than once.

St Kilda's Brendon Goddard, a star in last year's two grand finals, revealed last night that he had been subjected to surprise early-morning tests at his home twice in three days on the eve of this season.

"We're the first professional sport and one of the only sports to test for human growth hormone and EPO and we do as part of that test, at least 20 to 30 tests for HGH each year," Anderson said.

"I'm as confident as I can be (that players are not flaunting the rules), but you can never be 100 per cent sure on these things, which is why you need to make sure we are doing everything we possibly can to protect the integrity of our sport.

"There are a whole range of reasons (for target-testing), but any sort of big change in performance, change in body shape, best-and-fairests, success are all factors in the information used to make sure that we're using those tests in a smart way."

Melbourne sports physician Peter Larkins said he believed there was a 36-hour window where testers could detect HGH or EPO in a player's system.

"Anyone is naive to think that top-level sport doesn't look at the sort of things that might improve performance," Larkins said.

"We've seen that historically in many sports where we didn't think drugs were present and subsequently, something comes out. In terms of the value of EPO for endurance and growth hormone for strength and recovery, they would both benefit footballers, no doubt."