ASADA will pursue Essendon players over doping allegations after trumping the club in its court battle.

Doping allegations will proceed against Essendon players after the AFL club lost its high-stakes court battle with Australia’s anti-doping authority.

Federal Court Justice John Middleton rejected Essendon’s claims of an illegal investigation into its 2012 supplements program, ruling that the Australian Sports Anti-Doping Authority (ASADA) acted lawfully.

“The nature and conduct of the investigation was lawful,” he said on Friday.

“In my view ASADA complied with the rule of law in establishing and conducting, in the manner and for the purposes it did, the investigation.”

ASADA will now pursue the doping allegations against 34 past and present Essendon players.

Essendon and coach James Hird argued that ASADA illegally recruited the AFL in its investigation, using the league’s compulsory powers to force the players and coaches to divulge information.

Justice Middleton said both Hird and the Essendon players voluntarily entered into a contract with the AFL subjecting them to the league’s code.

He said there was no suggestion they were unaware of those contractual obligations, and they “voluntarily and directly” answered questions in front of both AFL and ASADA representatives.

“ASADA did not use any compulsory power of its own,” Justice Middleton said.

“Mr Hird and the 34 players voluntarily and directly gave to the AFL the answers to questions and the information without complaint.”

Even if there was no joint probe, Justice Middleton said the AFL could have independently compelled the players to provide the same information, then volunteered those details to ASADA.

“No useful purpose would be served by setting aside the notices or the grant of injunctive relief sought by Mr Hird and Essendon, because the process set out above could then be undertaken by the AFL and ASADA,” he said.

ASADA’s interim investigation report, which the AFL used to ban Essendon from the 2013 finals and suspend Hird for 12 months, was also provided to the league lawfully, Justice Middleton ruled.

ASADA CEO Ben McDevitt said the authority had been vindicated by the court’s ruling and the players must now respond to the allegations.

“These players still have a case to answer under the World Anti-Doping Code and Australia’s National Anti-Doping scheme,” he said in a statement.

“Our aim has always been to expose what happened at Essendon in 2012 and we steadfastly remain committed to this.”

Essendon is considering an appeal, with the club saying it’s very disappointed by the court decision.

“I think this is about the players and we’re very disappointed for the players,” Hird told reporters.

Justice Middleton also found the former Labor federal government had pressured the then-ASADA chief executive Aurora Andruska to bring the investigation to a conclusion, but said it had no impact on his ruling.

“Ms Andruska was under some pressure from the then-federal government and the AFL to bring the investigation to an end as soon as possible, and to assist the AFL so that the AFL could take disciplinary proceedings against Mr Hird and Essendon prior to the 2013 AFL finals,” he said.

“However I do not regard such pressure as giving rise to any dereliction by Ms Andruska in respect of her responsibilities.”