Federal Court Justice John Middleton will deliver his judgement on the Essendon supplements saga this Friday, September 19.

Essendon and coach James Hird are challenging the legality of the Australian Sports Anti-Doping Authority's investigation.

The judgement will be delivered at 1.30pm AEST at the Federal Court in Melbourne, and live television coverage will be provided.

A three-day trial in August heard sensational evidence from Hird and the former chief executive of ASADA, Aurora Andruska, about the handling of the supplements saga.

However, Justice Middleton's finding is expected to come down to a question of law.

If he rules in favour of ASADA, its chief executive Ben McDevitt will be free to pursue show-cause notices against 34 past and present Bombers players.

If Justice Middleton rules in favour of the club and its coach, ASADA will potentially need to decide whether to conduct a fresh investigation.