Wallis, a two-time premiership player, is understood to have called AFL chief executive Gillon McLachlan and former Essendon chief executive Ian Robson, making serious allegations and threats.

Wallis and another former employee, John Elliott, have made serious allegations about the club as part of a compensation claim after losing their jobs at the club. Elliott's father, also named John Elliott, is understood to also be the subject of a police blackmail investigation.

The AFL advised Essendon to go to the police with a blackmail complaint after the club had sought the league integrity unit's help in how to deal with the two disgruntled former employees.

The Bombers executive team is understood to have contacted the AFL's integrity unit several weeks ago in part to alert them to the serious allegations that were being made about the club in a Workcover claim and secondly to seek advice on how to handle threats that were being made against the club and individual employees.

Xavier Campbell is understood to have informed the league that demands had been made for money by Wallis as part of the compensation claim but also by Elliott Snr that unless money was paid then they would go to the media with serious allegations.

News Corp Australia on Thursday published a sworn statement by the pair as part of the Workcover claim. They alleged cocaine use and sexual harassment claims at the club involving at least one senior figure had been covered up. They further alleged that the club had been in negotiations with underworld figure Mick Gatto at the height of the Stephen Dank, Shane Charter drug-injecting saga.

In a TV interview on Thursday night, Gatto claimed he had been approached by Essendon to help "sort out" the supplements scandal, but that he had also approached the club on behalf of biochemist Charter.

Essendon chairman Lindsay Tanner released a statement on Thursday night claiming Gatto had contacted the club offering his services, not the other way around.

"As previously stated, Essendon CEO Xavier Campbell has had no dealings with Mick Gatto and kept the AFL Integrity Department informed at all times," Tanner said.

"I am advised by my predecessor Paul Little that he was approached by Mick Gatto offering his services and this offer was declined." The club strenuously denied these allegations and it is understood these were among the allegations which were threatened to be made public that were at the heart of the blackmail claim.

Wallis and Elliott signed sworn statements for investigators also alleging a fraud involving the healthcare rebate. The pair claim to have blown the whistle on the scam to senior club officials only to be told to keep quiet about the claims.

The AFL Integrity Unit, which employs former senior police officers, advised Essendon that the seriousness of the threats and allegations warranted them making a complaint to police.

Victoria Police on Thursday confirmed they were "investigating a report of a blackmail matter. As this investigation is ongoing, it would not be appropriate to comment further at this time".

Workcover investigated the claims made by the pair who had both lost their jobs at the club - Wallis had been an assistant coach who did not have his contract renewed and Elliott, who had been hired by James Hird at the time of his arrival as coach was made redundant after a department restructure.

Workcover interviewed more than a dozen current and former Essendon employees as part of its investigation and rejected the Workcover claim. Elliott is appealing the Workcover decision. The pair has also made a claim against the club's insurer for stress.