AUSTRALIAN Sports Anti-Doping Authority chief executive Ben McDevitt won't be attending next week's Federal Court trial.

Essendon and suspended coach James Hird are challenging the legality of ASADA's joint investigation into the club's 2012 supplements regime.

So far Bombers chairman Paul Little and chief executive Xavier Campbell have represented the Bombers in court. Hird is expected to attend the trial now he's returned from France.

But McDevitt has remained in Canberra throughout proceedings to date, and will remain absent during next week's trial which is slated to last three days.

"ASADA CEO Ben McDevitt will closely follow the proceedings, but will not be attending the Federal Court case in person," an ASADA spokesperson confirmed to AFL.com.au on Thursday.

Essendon and Hird initiated legal action against ASADA after McDevitt issued show-cause notices to 34 present and past Bombers players.

McDevitt, a former deputy Federal Police commissioner, assumed his new role as boss of the anti-doping watchdog in May.

Just over a month later, he issued the show-cause notices.

The trial, before Justice John Middleton, begins in Melbourne on Monday.