The anti-doping body probing Essendon’s controversial supplements program unlawfully used the AFL to escape the limits of its own powers, say lawyers for Bombers coach James Hird.

Hird is seeking to discredit ASADA’s joint investigation with the AFL for a second time after a Federal Court judge found the probe to be legal in September.

Hird’s barrister Peter Hanks QC on Monday said the Australian Sports Anti-Doping Authority had illegally recruited the AFL to force Essendon players to answer questions.

He told the full bench of the Federal Court there was no doubt ASADA could ask questions and request documents, but it had no powers to compel those being questioned to answer or deliver the documents.

Essendon players and staff are forced to answer questions put to them by the AFL or face penalties under the contracts they sign with the league.

“The AFL’s presence was plainly desired by ASADA in order to provide the compulsion,” Mr Hanks said.

“By having the AFL present the gate was opened to that disclosure.

“It’s to circumvent, to walk around the limits on its power.

“It was very convenient and efficient but it was unlawful.”

Mr Hanks said ASADA ran the interviews, asking the bulk of the questions with the AFL “topping and tailing” and asking its own questions at the end.

He said the legislation governing ASADA at the time of the 2013 investigation entitled it to be “assisted by and delegate to specific individuals” but those did not include a sporting body like the AFL.

Justice John Middleton in September ruled that ASADA acted lawfully by conducting a joint investigation with the AFL into Essendon’s 2012 supplements program.

After that finding, ASADA issued show cause notices to 34 current and past Essendon players.

The appeal continues.