The head of Australia’s anti-doping agency has launched a scathing attack on the sports scientist who ran controversial supplement programs at the Cronulla and Essendon football clubs.

ASADA chief executive Ben McDevitt said Stephen Dank should never be able to work in sport ever again.

“If what we have gathered in relation to Stephen Dank’s activities is tested and proven, then in my view, and my strong recommendation is that Stephen Dank never ever should be allowed near any sporting venue or any athlete, anywhere in the world, ever,” he told the ABC’s Offsiders program.

The comments come after 12 past and present Cronulla Sharks players were handed 12-month bans for breaching doping regulations back-dated to last November.

For most, that is effectively a three-game suspension.

Mr McDevitt said there is clear evidence the players took banned substances and defended criticism that the penalties were too lenient.

“These players have gone on the field to play with those substances in their systems and that has given them an unfair advantage. That’s a fact,” he said.

“In relation to these particular players, their claim is that they took performance enhancing drugs unwittingly. They are saying they were doped and they were duped.

“On the evidence that we have gathered that is also a fact and that entitles them to a reduction in the penalty.

“It is a fact that they have a claim here to be able to educe that penalty to a one-year penalty due to them having no significant fault.”

ASADA has come under fire for its handling of the investigations into supplement use in the AFL and the NRL.

Mr McDevitt said the agency was not equipped to deal with the investigation.

“The reality is that I don’t think ASADA was ready for an investigation of this magnitude,” he said.

“I can tell you something – it’s not just ASADA. I don’t think any national anti-doping organisation in the world would have been ready for something of this magnitude, of this complexity, of this enormity.”

Mr McDevitt is confident the World Anti-Doping Agency (WADA) would stand by ASADA’s handling of the situation.

I think we’re on extremely firm ground,” he said.

“I’ve been consulting with WADA and the advice I have from WADA is that they are very comfortable with how this was handled and the landing point that we have arrived at.

“Obviously WADA will always retain their right to appeal.”

On Saturday, Dank was officially banned from the NRL over his involvement in the Cronulla Sharks’ 2011 supplements program.

Mr McDevitt was asked if it is possible that players from the Essendon Football Club could get similar backdated bans.

“There is just no way that I could contemplate answering that question at this point in time until I’m able to fully consider the judgement which will come from Justice Middleton and the implications of that for all parties,” he said.