Group One-winning jockey Gary Doughty has been suspended from riding trackwork after a urine sample showed traces of a sleeping pill he says he took more than a day before the test.

Doughty trains a team on the Gold Coast and as a former jockey he rides many of his horses in trackwork.

Integrity officers took a urine sample from Doughty during a general sweep at the Gold Coast on August 19.

Doughty's sample showed traces of oxazapam and temazepam which are used in many general sleeping pills.

At a stewards inquiry, Doughty pleaded not guilty and explained it was medication prescribed by his doctor.

He said he used the medication infrequently.

Doughty argued that his judgment when riding trackwork that morning wasn't impaired as it was 25 hours since he took the sleeping pill.

However, stewards found Doughty guilty of not making the appropriate application for an exemption to ride trackwork with this medication and he was in breach of the rule if a banned substance is detected in a sample.

While Doughty was suspended from riding trackwork for three weeks it does not affect his licence to train.

"I woke up at 3am on the Sunday and couldn't get back to sleep," he said.

"I had some tablets my doctor had given me earlier and I took one sleeping through to 9am.

"I felt fine, slept Sunday night without a sleeping pill and went to trackwork where I gave a test."

"I explained what I had taken and it was 25 hours beforehand. But while the drugs are out of your system inside a day they can still show up in a urine test."

Doughty said he had a clean record for 45 years and was upset the charge could be on his record.

"I reckon I'm not the only racing person to take a sleeping pill so be careful," he said.

Doughty is seeking an internal review of the decision.