The Australian Trainers' Association wants Racing Australia to step in to resolve an on-going saga of positive swabs in Victoria to equine products containing altrenogest

ATA chief executive Andrew Nicholl said commercially sourced products containing altrenogest were widely used in racing stables across the country.

They were an essential medication for regulating the cycles of fillies and mares.

A Racing Victoria stewards notice in June warned trainers and vets to stop using products containing altrenogest as samples had returned levels of trenbolone, as well as trendione, an anabolic steroid and a banned substance under the rules of racing.

They issued another notice on Wednesday while last month Racing NSW introduced a threshold of one microgram per litre.

With spring racing in swing, regulating fillies and mares cycles is required to help moderate their behaviour to optimise race performance.

Nicholl says he can't be critical of RV who have single handedly shouldered the responsibility of getting to the bottom of the trenbolone positives.

"I think Racing Victoria has been diligent through their process of elimination," Nicholl said.

"From their investigations, the evidence points towards a problem at the source where the compound, altrenogest, is sourced and subsequently engineered.

"But more importantly it's what we do from here on in.

"We need Racing Australia to get involved and see whether there is a better solution, ideally a solution that gives us back what we had before this problem surfaced."