An inquiry into the alleged drenching of 2013 Tamworth Cup winner Prussian Secret has been delayed.

Trainer Cody Morgan had been scheduled to appear before Racing NSW stewards on Wednesday but the panel has agreed to postpone the inquiry until July 27 at the request of Morgan's legal counsel.

The inquiry centres around whether Prussian Secret was stomach-tubed before his win in the Tamworth Cup in April 2013 and before he was withdrawn from the Gunnedah Cup the following month.

Morgan and harness racing trainer/driver Robert Clement were both found guilty in Tamworth District Court last month of engaging in conduct to corrupt the betting outcome of the 2013 Tamworth Cup.

A jury found Morgan and Clement guilty of drenching Prussian Secret before the race.

Police from Strike Force Trentbridge arrested Morgan en route to the Gunnedah race meeting on May 12, 2013.

Morgan and Clement were the first people to be charged under NSW race-fixing laws introduced in 2012.

They are expected to be sentenced at the end of this month.