Cobalt irregularities have appeared in swab samples taken from Queensland-trained racehorses, the state's peak racing body has revealed.

Racing Queensland sent a batch of urine samples to the National Measurement Institute in September 2013 when intelligence first emerged regarding cobalt use in harness racing.

"Our trainers were then made aware we would be testing for cobalt in October 2013 and a number of samples from both thoroughbred and harness horses have been frozen since then in anticipation of the new threshold," Racing Queensland's integrity spokesman Wade Birch said.

"These samples are in the process of being split to obtain a B sample for further testing, in accordance with state legislation, which includes the need for the process to be filmed in its entirety."

Birch has moved to clear a grey area in the crackdown on cobalt use in the racing industry as prominent Melbourne trainers Peter Moody, Mark Kavanagh and Danny O'Brien are being investigated for positive swabs.

Australian racing officials introduced a threshold level for cobalt in racehorses which came into place on January 1.

Birch said trainers and owners who were uncertain if they can be held responsible for samples taken before the introduction date should remember that cobalt has always been an illegal substance.

"It is impossible for a horse to have a cobalt level above the threshold through environmental contamination," he said.

"Therefore if the test is above the threshold it would allegedly have been applied illegally and those found responsible are open to charges."

He said any test result on which action would be taken would involve a level which was impossible to reach through other means such as contamination.

Birch said Queensland legislation was stringent in relation to testing methods.

"It ensures all sampling activity is conducted with the utmost integrity in the interest of Racing Queensland as the control body and the trainer," he said.

He said if any of the samples, which include those taken from last year's Winter Carnival, were found to exceed the threshold, the offending trainer could be subjected to lengthy bans.

"We make no apologies for this stance and trainers have had ample warning that as soon as the testing capabilities were in place, we would pursue this course of action," he said.