The Cambridge trainers Murray and Bjorn Baker have been fined $15,000 and their three horses Nom De Jeu, Fully Fledged and Mountain Road disqualified for wins at Te Rapa in Hamilton last month, after they tested positive for a banned substance.
The horses tested positive for Ranitidine, a drug which is generally used for the treatment of stomach ulcers.
Racing's rules dictate horses must be drug-free on race days.
Trainers are guided by withholding times for the medical drugs they administer to horses between their races.