Trainer David Vandyke has been fined $12,000 after a filly, who is no longer in his care, retuned a positive result to a bronchodilator banned on race day.

Trainer David Vandyke has been hit with a $12,000 fine for sending Queen Tara to the races with the prohibited substance ipratropium in her system.

The bronchodilator was detected in a urine sample taken from the filly after she finished second in a race at Wyong on April 30.

At the time, Vandyke ran a stable at Randwick for Segenhoe in addition to his Warwick Farm stable.

Racing NSW stewards warned Vandyke in October that the withdrawal period for the substance was five days.

Although Vandyke had issued instructions to the senior personnel at the Randwick stable of the withdrawal period, the communications were ignored with the stable vet applying a three-day time limit.

Stewards said the communication protocols put in place by Vandyke and the stable were deficient with senior staff in consultation with veterinary personnel able to make decisions regarding treatments and withdrawal times without reference to the trainer.

They said the advice given by the stable vet about the withdrawal period was incorrect and not in accordance with published information.

Computerised treatment records indicated the administration on five occasions of ipratropium to horses in the weeks leading up to the 30th April 2015, applying a three-day withdrawal time, a matter that should have been detected by Vandyke.

The Segenhoe horses at Randwick are now in the care of John Sargent.