Queensland stewards have confirmed they are investigating cobalt irregularities from two thoroughbred stables and one harness racing stable.

Chief steward Allan Reardon said the three irregularities had been detected by Racing Queensland's new testing machine bought earlier this year.

"The B samples have now been sent on for a confirmation of the results. Our policy is not to release names or races until the B samples have confirmed our tests," Reardon said.

However, Reardon did confirm the irregularities did not relate to any major race.

North Queensland trainer Glen Baker was disqualified for two years for a cobalt positive from French Lesson who won at Doomben in January.

His appeal will be heard on July 17.

Central Queensland trainer Jamie McConachy's case involving a positive to 2014 Rockhampton Cup winner Vandalised is still being heard.

Stewards have been unable to contact former trainer Len Treloar regarding an alleged cobalt irregularity found in one of his horses last year.