Harness racing trainer Rachel Scott has had her sentence on a cobalt charge reduced in a case which could also have an impact on thoroughbred racing.

Scott was charged with bringing Nolonga Your Choice to race with a prohibited substance in its system at Redcliffe on April 2, 2016.

She was sentenced to a 15-month disqualification after the horse was found to have levels of cobalt above the allowable limit.

Scott, who pleaded not guilty, was unsuccessful in an internal review and appealed the sentence to the Queensland Civil and Administrative Tribunal.

In a written 18-page judgment, QCAT member Jeremy Gordon set aside the disqualification and imposed a three-month suspension and $6000 fine.

It means while Scott cannot nominate her horses for races, she can continue to work around her stables.

The inquiry heard submissions that the cause of the offence was found to be a build-up of cobalt levels over time because of carelessness in the feeding and supplement regime.

Member Gordon's judgment included a close look at many other cobalt cases from harness racing and thoroughbreds.

"I am satisfied that Scott believed that her feeding and supplement regime was a legitimate and normal one for a racehorse. I am satisfied she was not trying to go close to the permitted level of cobalt; she had no idea how close to the permitted level of cobalt her feeding regime was putting the horse," Gordon said..

"She had no idea that what she was feeding the horse could cause a build-up of cobalt to the extent that the horse became saturated with it."

He found while Scott should have known, in his view the level of blameworthiness could be called moderate carelessness.