A shocked Kevin Moses will fight a 12-month ban for presenting a horse to race with cobalt in its system.

Although the trainer was not charged with administering the substance, Racing NSW stewards said on Friday the offence was serious and warranted a period of disqualification.

"How, what, where and why has not been established and you have not been charged with administration," chief steward Ray Murrihy said.

"But a cobalt positive brings a certain amount of discredit to the industry."

A pre-race sample taken from Felix Bay before he raced on April 16 at Hawkesbury showed a level in excess of the 200mcg per litre of urine threshold.

So sure was the trainer that Felix Bay had received nothing untoward he gave the go-ahead for the gelding to race after being told of the elevated level.

"I've never touched cobalt," Moses said.

"Why would I hit a $7000 horse in a (benchmark) 75 with it?"

Moses' wife and foreperson, Jenny, told the inquiry she was the only one in the stable apart from the vet authorised to give injections to horses and Felix Bay had received vitamins the night before.

Racing NSW senior vet Craig Suann said recent studies showed a dramatic decrease in cobalt levels within four to six hours of injection with substances containing it such as VAM.

He said his opinion, based on those studies, was that the levels found in Felix Bay indicated he received the substance on race day.

Moses and his wife said they had taken little notice of the publicity surrounding recent cases because they did not believe they were using products containing cobalt.

"I never read the warnings because we don't use it," Jenny Moses said.

"I didn't know so many products had it in them."

That element of the case was one chief steward Ray Murrihy said the stable had failed to address.

"The responsibility is with you to know what is in the stable products and to read all the necessary publications.

A three-time Sydney premiership-winning jockey, Moses took out his training licence in January 2002 and until Friday had not been charged with any offences.