Queensland trainers are disappointed integrity officers have refused to introduce a local rule to allow the use of the drug altrenogest which many believe is essential to preparing mares.

Trainers have been asking for a local rule to supplement the national rule regarding the use of the drug which can be used to regulate the reproductive cycles of fillies and mares.

It is currently exempted for use in its pure form but can produce detectable amounts of the anabolic steroids Trendione and Trenbolone .

Racing NSW has introduced a threshold for "non-consequential" amounts of the two substances.

The secretary of the Queensland branch of the Australian Trainers Association, Cam Partington, said at a time when animal welfare was a big issue the use of the drug was important.

"We were keen for Queensland to follow NSW and we have been pushing the issue for nearly a year. It is disappointing QRIC has decided not to go ahead with a local rule," Partington said.

QRIC boss Ross Barnett said problems in the production process led to the anabolic steroids being detected as impurities in altrenogest.

In October, 2018 QRIC officially warned participants about the risks of using the drug on this basis. This warning was consistent with advice issued nationally.

"The national rule states that if a prohibited substance is detected in a racehorse prior to or following the running of any race the horse must be disqualified and its detection constitutes a breach of the rules for the trainer or person in charge of the horse," Barnett said.

Barnett said he sought independent legal advice which has ruled out consideration of a supplementary local rule.

"The legal advice is clear that a local rule cannot override the application of the relevant national rule, so on the basis of that advice the introduction of a Queensland local rule is not practical and is not supported," he said.

"We respect the right of other states to respond to this issue as they consider appropriate but our position has now been clarified.

"Settling the legal position has meant that we have not had to further consider other issues including the unintended, but clear, performance enhancement benefit to a treated animal that would occur pre-race as a result of the presence of the prohibited anabolic steroids.

"It is that demonstrated performance enhancing benefit that sees these products on the banned list.

"Stewards will now consider any outstanding prohibited substance matters and deal with each of them on their merits."