There were 15 positive tests in 2013, down from 26 in 2012, but there are four players on two strikes. A positive strike remains next to a player's name for four years.

AFL operations manager Mark Evans warned players on Friday that the league would alter its program depending on what their social habits were.

These issues typically arise over a weekend, including the bye weekends when players often return to their home town.

The illicit drugs policy was upgraded last year when clubs expressed increasing concern about the risks some of their players were said to be taking. Collingwood chief executive Gary Pert even warned of "volcanic behaviour".

“My view is, we have had 15 players who we have been able to detect early and put through a very specific and targeted program about them their reducing their risk and protecting their health. I think that is a good thing," Evans said.

“The illicit drug policy was strengthened last year on the back of the high figures in 2012. In the face of industry concerns, we limited self reporting to one per career, we certainly increased the number of tests at the start of the week and we are very much smarter in the way we conducted those tests.

"We also built in the ability for us to have conversations with clubs and provide the identity to de-identified data to their CEO and the key people in their football departments and also to their boards to try and engage them about the things they can do to work with their playing group again to reduce the risks.

“We know over time this (positive figure) will go up and down and we will have to change our strategies and our approach.”

The AFL's chief medical officer Dr Peter Harcourt said that in 2013, a total of 1998 tests were conducted, with no match-day positives recorded and 15 out-of-competition detections. This represented a 0.75 per cent detection rate.

Harcourt said stimulants were now the drug of choice. As is a growing issue in the wider community, cocaine and ice fall into this category.

“There has been a shift away from cannabis. Cannabis is quite rare in this group. Most of the issues we are dealing with are stimulants, which pretty much reflects what you are in reading in the papers from other communities and the issues that are out there," Harcourt said.

Under the changes made last year, players are now limited to one self-report through their careers. This means they can admit to taking a banned drug and escape a strike.

Harcourt wouldn't reveal the specific number of players who had self-reported in the past year, only confirming it was  fewer than the 15 positive strikes.

He said the upgraded policy agreed  upon by players, clubs and the league had also had an impact on those with two strikes.

“There is a lot more target testing going on, monitoring individuals and making sure they are understanding their accountability and vulnerability with their increased testing. (This) is probably the big change in the last 12 months," he said.

Target testing can see players tested at all hours any time of the day and or night.

Only one player, former Hawthorn player Travis Tuck, has ever recorded three strikes under the policy. Tuck's third strike came only because he was found in a distressed state by police.

A player can avoid testing when he has two strikes if he is having drug treatment. However, if he has a problem, the AFL says he will not be permitted to play - a situation that is believed to have occurred.

AFL Players Association acting chief executive Ian Prendergast said: "This is the most developed illicit drug policy in world sport and we strongly believe the medical approach to drug use is the best way to protect players’ health.”