There are fears Australia's ice epidemic has moved to the race track, with horses from a Hunter Valley stable the first in the state to test positive to the banned drug.

Racing New South Wales stewards said methylamphetamine was found in samples from three horses trained by Luke Griffith at Scone.

An inquiry was launched after swabs were taken from two winning horses that raced at Tamworth on January 18.

The third positive test involved a filly that won at Taree in February.

Mr Griffiths currently leads the Hunter and north-west trainers premiership and has been told the inquiry will also look at samples taken from his stable personnel.

Chief steward Ray Murrihy said he had never seen ice detected in a horse swab.

"No, it's the first time in my experience," he said.

"It is reported to be a central nervous system stimulant.

"We have seen it obviously in rider and stable hand samples and there have been significant penalties handed down by stewards for a number of years with those findings."

Mr Murrihy said he was waiting for the results of an inquiry.

"We must go in with an open mind," he said.

"We have the advantage of having both the veterinarians and the analysts to give us further value-added information, as well as our investigators who will look through the circumstances of it."