THE WIFE of suspended Essendon coach James Hird has revived the explosive allegation that AFL chief executive Andrew Demetriou tipped off the club about the supplements scandal.

The outgoing AFL boss strenuously denies the claim, first raised in July last year, that Demetriou spoke to then-Bombers chairman David Evans shortly before Essendon came under ASADA and League investigation.

Tania Hird, who is a lawyer, said she was listening on a speaker phone when her husband spoke to Evans on July 25.

"I was taking notes - I take a lot of notes," she told the ABC's 7.30.

"David admitted that he said to James 'go into ASADA and tell the whole truth, but don't say what Andrew Demetriou told us'.

"It has been referred to as the tip-off.

"James did say in return 'if I'm not asked about it, I won't offer it up, but if I'm asked about it, like anything I'm asked about, I will answer it honestly and truthfully and to the best of my knowledge'."

Her claims were broadcast on Thursday night, a day before Essendon starts its season against North Melbourne at Etihad Stadium.

In late July last year, Evans suddenly resigned from Essendon because of health issues and a month later Hird received a 12-month suspension from the AFL.

Essendon remains under ASADA investigation.

Last July, the Herald Sun reported that Demetriou spoke to Essendon officials on February 4, the night before the Bombers announced they would come under AFL and ASADA investigation.

Demetriou denies discussing with Evans a confidential Australian Crime Commission report the AFL had received a few days previously.

The AFL boss adds no specific club was mentioned in the ACC briefing.

"We were told prior to the announcement that there was going to be an investigation into Essendon involving performance-enhancing drugs or supplements," Tania Hird said.

"We were told that at a time when we shouldn't have been told that."

The AFL declined to comment about Tania Hird's claim.

She added her husband only agreed to his 12-month suspension because of bullying from AFL officials.

Hird is now in France on a study trip, with Tania and their children to join him later this month.

"He didn't plead to any breach of the player rules, he wasn't found guilty of any breach of the player rules," she said.

"In the end it was the threats and bullying of the AFL to the club and to himself.

"It is a really great game, but at the moment it is an industry where there are a lot of people who are frightened about speaking the truth, about speaking their mind."

Hird's AFL suspension ends in August.