LACHIE Keeffe and Josh Thomas' shock positive tests to a performance-enhancing drug have failed to change the behaviour of AFL players when it comes to illicit substance use, Collingwood CEO Gary Pert believes.

The Magpie pair was banned for two years after testing positive to clenbuterol, which they believe was inadvertently ingested while they were using illicit drugs during the off-season. 

Pert said players' use of illicit drugs remained "the biggest issue in the AFL", despite the fate suffered by Keeffe and Thomas after their positive tests in February last year.

"I honestly thought this would be something that would fundamentally change the attitudes and behaviour of all sportspeople, not only AFL footballers," Pert said.

"For a short period of time it had shock value, but as a long-term solution to this high priority, [player behaviour] has not fundamentally changed." 

Pert also said the AFL's recently revised Illicit Drugs Policy could be improved further to address what he famously described in 2012 as the "volcanic behaviour" of players in the off-season.

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He called for the policy, to which the players voluntarily agree, to be debated again during the upcoming collective bargaining negotiations.

Pert said he based his concerns on ongoing discussions with drug experts, police, players and past players.

"This is still an ongoing problem and we need to come back and review that policy again and I think it is going to be an ongoing thing," he said. 

While praising players and the AFL for being prepared to review the policy last year Pert said many clubs still questioned whether the medical model went far enough to change behaviour.

"We have got a model that everyone can see has a bigger consequence for certain behaviours at certain times of the year and less of a consequence at other times of the year," he said.

"I think that could be part of the drivers that are dictating the behaviour at that time of the year."

As part of the revised IDP, players were hair-tested last year for research purposes and to direct target testing and education programs.  

The AFL and the players' association also reached agreement that numbers of positive tests from urine tests, previously released publicly, would be kept confidential.

Several sources, including players, have described the off-season behaviour by some players as "disappointing" to AFL.com.au, although numbers have remained confidential.

A revised policy was announced in October after negotiations between the AFL and players. 

It improved player education and counselling programs, had a mechanism for medical intervention if a first strike was detected.

Under the new policy, a player's identity becomes public after a second positive test. He also receives a four-match suspension and a $5000 fine.

A third strike results in a 12-match ban.  

Players in the AFL's Talent Pathway programs also undergo testing with detections of an illicit substance to be communicated to the respective club doctor once drafted.

The AFL has been discussing the issue in its annual meetings with clubs and AFL.com.au understands the League wants the current policy to be given time to take effect. 

Players have long held a view that they should be praised for being prepared to agree to a voluntary policy and is frustrated at the community's constant questioning of the policy. 

Pert believed the issue would be an ongoing priority for the foreseeable future.