Two prominent Victorian trainers found guilty of administering cobalt to their racehorses could face three-year bans for their conduct.

Danny O'Brien and Mark Kavanagh were found guilty in December of the administration of cobalt for the purpose of affecting the performance of a horse in a race.

Four O'Brien-trained horses and the Kavanagh-trained Magicool returned levels of cobalt above the 200 micrograms per litre of urine threshold in races in 2014.

Unless there are special circumstances, the minimum penalty is a three-year disqualification.

Vet Tom Brennan was also found guilty of cobalt charges.

He admitted adding a substance called Vitamin Complex to intravenous drips given to the horses at the two stables but denied knowing it contained a high concentration of cobalt.

Final submissions on what penalties the men should receive will be heard by the Racing and Appeals Disciplinary Board on Tuesday.

Following the guilty verdict on December 23, O'Brien said he was looking forward to having the penalty hearing finalised so they could move the case to the Victorian Civil and Administrative Tribunal.

The trainers are disappointed their lawyers were unable to cross-examine Racing Victoria chief steward Terry Bailey and Dion Villella, from RV's Compliance and Assurance Team, during December's seven-day hearing.

They hope by going to VCAT they will be able to subpoena and question officials.