An investigation is underway into the discovery of what appears to be a banned blood doping substance at an Ashburton racing stable.
Racing Integrity Unit general manager Mike Godber says a syringe labelled as containing "EPO" was found during a routine visit by inspectors.
He says four horses from the stable were ordered scratched from races on Saturday and on Monday, although the trainer involved denied any of the horses had been given the substance to improve their performance.
Blood samples from the horses are being examined. Any further action by the Racing Integrity Unit will be decided after the test results are known later this week