Popular Warwick Farm trainer Gary Portelli has been fined $6000 after one of his horses tested positive to Ibuprofen.

Portelli pleaded guilty to a charge of bringing a horse to the races with a prohibited substance in its system after the anti inflammatory was found in a pre-race sample taken from Za Magic at Rosehill in September.

Racing NSW stewards noted it was Portelli's first such offence in his 23-year career. Za Magic was disqualified from the race in which he finished ninth.