Bombers coach James Hird's lawyer questions ASADA powers

Essendon coach James Hird's battle to discredit ASADA's investigation into the club's supplements program will focus on the extent and limits of its powers.

The Bombers coach returned to the Federal Court today to appeal against the court's decision to uphold the Australian Sports Anti-Doping Authority's joint doping probe with the AFL.

Hird's barrister Peter Hanks QC said the appeal would focus squarely on what ASADA was empowered to do.

"What power was there to conduct an investigation of the kind it did conduct?" Mr Hanks said.

"What was it authorised to do?"

Mr Hanks told the full bench of the Federal Court there was no doubt ASADA could ask questions and request documents as part of its investigations.

But he said it had no powers to compel those being questioned to answer or deliver the documents.

He also said the rules made it clear the investigation was to be independent, not run jointly with sporting bodies such as the AFL.

"The investigation is a matter for the authority, the authority is to conduct an investigation that's independent of the sporting body, which passes it over," he said.

Hird's legal team says it will be relying on the legislation that was relevant to ASADA in July last year.

The act has since been updated to broaden ASADA's powers.

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

In the wake of that finding, ASADA issued show cause notices to 34 current and past Essendon players.