THE WORLD Anti-Doping Agency's appeal against the AFL Anti-Doping Tribunal's decision earlier this year to clear 34 past and present Essendon players of doping charges will be heard in the Court of Arbitration for Sport in Sydney this week.

Essendon CEO Xavier Campbell said on Sunday the hearing would take place on a confidential basis.

"The club is not a party to the proceedings so we will not be represented inside the hearing," he said.

"We will do our best to keep members updated with as much information as possible but we must continue to respect the confidentiality of the process and the hearing.

"The players, both past and present, are being well represented by their legal team, similar to the AFL Anti-Doping Tribunal earlier this year.

"We remain confident in the players' position and will continue to support the players, both past and present, and their families during this time.

"While there are no guarantees, all indications from the CAS and players lawyers suggest that it is likely a decision will be handed down prior to Christmas.

"Our players have been incredibly resilient throughout this process and we ask that our members and fans continue to support them in this final stage of the process."

Former Australian Sports Anti-Doping Authority head Richard Ings said on Friday WADA would need to produce "something new and different" to win the case.

"A highly-esteemed panel of arbitrators (the AFL anti-doping tribunal) have reviewed all the evidence and found that the players did not have a case to answer," Ings told AAP.

"WADA will have to produce something new and different to convince a group of CAS arbitrators if they hope for a different outcome."