In its defence lodged with Justice John Middleton in the Federal Court, and released publicly on Friday afternoon, ASADA denies claims from Hird and the Bombers that it conducted an unlawful investigation into the club's 2011-12 supplements program.

However, should the anti-doping body lose its case, ASADA - through chief executive Ben McDevitt and lawyer Craig Rawson - have issued what looms as a chilling warning to the 34 current and former players issued with show-cause notices.

"Even if ASADA obtained information unlawfully in the course of the joint investigation (which is denied), the grant of relief should be refused on discretionary grounds because ASADA could lawfully obtain all the exact same information (again) by the issue of disclosure notices under Division 3.4B of the NAD Scheme, and then issue fresh show-cause notices to the EFC players," the document said.

The 34 players are alleged to have been administered the banned drug Thymosin beta-4. They have opted to not be a party to the case brought by Hird and the Bombers.

The Bombers and Hird want the investigation deemed illegal, meaning the show-cause notices would be void. However, ASADA has maintained it could reissue the notices with information secured after the joint investigation was completed in August last year.

That it now claims it could secure the "exact same information" - meaning it could use the interviews given by players early last year - appears to highlight its determination to win the case and have players forced to show why they should not be added to the Register of Findings, the first step towards the issuing of infraction notices - and bans.

Lawyers for the Bombers and Hird did not wish to comment on Friday night.

ASADA does admit that it "agreed to provide information obtained by the AFL to ASADA for the purposes of ASADA's investigation" but claims it opted to begin its investigation before, and independently of, deciding to work with the AFL.

ASADA also claims it "could lawfully have (passed on information to the AFL anyway) because the disciplinary action referred to was based upon the applicant and EFC personnel having brought the game into disrepute by virtue of poor governance and accountability with respect to the enforcement of the anti-doping rules. That is a matter connected with ASADA's investigation and the administration of the NAD (national anti-doping) scheme and within the purposes of the Act and the NAD scheme".

ASADA says it needed the AFL's compulsory powers to ensure players and officials could be interviewed and could not "claim the privileges against self-incrimination or self-exposure to a penalty".

"The AFL provided ASADA with immediate access to information provided by EFC players and EFC personnel at interviews (carried out pursuant to the exercise of the AFL's compulsory powers) by permitting ASADA staff to attend, jointly conduct and tape record those interviews."

The anti-doping body hit back at Hird's claims that he was not given the right to silence during his nine-hour interview last year. While he was warned that he had to tell the truth under the AFL's laws, Hird says under the anti-doping code he should have been reminded about his right to privilege.

"The applicant (who was legally represented at the time) advertently declined to claim any privilege or right against self-incrimination and raised no objection to the presence or role played by ASADA or to the provision of information to ASADA," Rawson wrote.

ASADA maintains Essendon supported the AFL and the anti-doping body working closely after it self-reported under then chairman David Evans.

"The applicant requested that the AFL and ASADA conduct a joint investigation in early February 2013 and thereafter expressed support for the conduct of the joint investigation," ASADA says.

ASADA has again denied its interim report was handed to then AFL chief executive Andrew Demetriou for an "extraneous" purpose other than the anti-doping case.

The case goes to trial on August 11 and is expected to last three days.