Champion Saint Nick Riewoldt has slammed the AFL's illicit drugs policy, saying players are exploiting loopholes in the system.

The comments come amid recent claims that players are using mental health conditions to avoid being tested for illicit substances. Former St Kilda coach Grant Thomas also sparked furore with his own revelation of widespread drug use at the club throughout his time as coach, a claim the former captain strongly denied.

The five-time All-Australian said players are taking advantage of the well-meaning nature of the policy.

"The AFL, by their own admission on their own website, what the policy is designed to do is to identify players with substance abuse issues and place support around them to protect their health and wellbeing," Riewoldt said on SEN Breakfast.

"Now, the vast majority of players donโ€™t have substance abuse issues, theyโ€™re taking the piss because the system allows it.

"Hair testing in the off-season and during the season, thatโ€™s only to identify the numbers.

"Thereโ€™s no recourse, thereโ€™s no ramifications, itโ€™s a free-for-all.

"It depends what your definition of out of control is.

"I would say itโ€™s out of control."

Riewoldt suggested the enforcement of harsher penalties would be more effective in discouraging players from taking recreational drugs.

"The blokes that are just doing it because they can, because the system allows them to get away with, youโ€™re telling me if theyโ€™re getting a four-week ban for first detection, theyโ€™re going to do it? I donโ€™t think theyโ€™re that stupid," he said.

"Theyโ€™re not going to do it because theyโ€™re going to get suspended and everyoneโ€™s going to know."

This would represent a stark contrast to the current policy, under which a player is suspended only when he tests positive for a third time.