Taking action against Essendon players over supplement use has been compared to charging a construction worker for getting an asbestos-related disease.

AFL Players' Association player relations manager Ian Prendergast made the comparison while outlining his version of the supplements saga before a Senate inquiry in Canberra on Friday.

The committee was taking evidence, under parliamentary privilege, in relation to proposed new federal laws to align Australia's anti-doping scheme with the world anti-doping code.

In arguing against the tough new penalties and the stripping of legal rights from athletes, Prendergast said Essendon players had received a raw deal and the scandal had affected their mental health and ability to perform.

"Compare the situation at Essendon to what would happen with workers in another industry, say the construction industry, where construction workers were exposed to asbestos through the lies of their employer," the former Carlton player told the inquiry.

"Would we be talking about punishing those workers, or would we be talking about compensating them?

"It's a very similar situation we are dealing with down in Essendon.

"It's already had a huge toll on these athletes, and if they are handed penalties then they have the potential to end their careers."

Former Bombers ruckman Paddy Ryder, who was traded to Port Adelaide on Thursday, revealed earlier this month he feared for the health of his unborn son.

Prendergast said there was "no suggestion whatsoever" that the Essendon players had cheated.

"In fact, they took a series of steps to ensure themselves that what they were to be administered as part of the supplements program did comply with the WADA code and had been ticked off by their club doctor," he said.

He said the players had engaged in a series of meetings to talk them through why they were going to be given the substances and this was consistent with the "education" they had received from the Australian Sports Anti-Doping Authority and the AFL.

If it was proven they had been administered banned substances, he said: "On the facts the players had been deceived, they've been duped".

Prendergast said the saga had taken a huge toll on the 34 players who had taken all the appropriate steps, and put their trust in their employer and sports medicine advisers, but had been subjected to a 19-month ASADA investigation.

He said the players wanted a clean sport.