Racing Australia has reaffirmed its position on cobalt and will not be making amendments to the Australian Rules of Racing.

The Australian Trainers' Association (ATA) wrote to Racing Australia (RA) in August asking the Veterinary and Analysts Committee (VAC) for its expert advice on cobalt.

The ATA letter raised a number of concerns about the volume of cobalt positives registered across all racing codes since 2014, including 100 thoroughbred trainers.

It said there was the ongoing debate over cobalt positive sources, in particular where legal, commercial products were leading to alleged rule breaches and the subsequent application of significant penalties.

The ATA pointed out other international racing jurisdictions, including England and Ireland, had appeared to soften their stance towards cobalt threshold breaches by introducing fines.

The cobalt threshold is set at 100 micrograms per litre in urine.

In their reply to the ATA, RA said the VAC remains staunch on its view that cobalt has the potential to positively effect performance, and is a welfare risk to horses at toxic levels.

It says there is no nutritional, medical or welfare justification for the administration of cobalt salts by injection.

RA says industry notices have been provided to trainers advising that administration of certain registered vitamin supplements close to racing, particularly by injection, may result in a sample exceeding the threshold.

"The ATA will need time to discuss the RA response in detail with its internal executive and external advisers," the ATA said in a statement.

"Once the ATA has established its formal position, it will in turn, produce an appropriate response to RA."