The Ministry for Primary Industries has confirmed the first case of the equine herpes virus has been found on a New Zealand farm.
The virus has already infected horses in Australia, Europe and the United States.
It causes symptoms such as fever, and affects a horse's co-ordination and balance.
The ministry is confident it has the disease kept to one farm. But it says horse owners need to be vigilant for signs of the disease and contact their vets if they are concerned.
