Horses in a mid-Canterbury stable on New Zealand's South Island have come down with what is suspected to be the highly contagious strangles disease.

Strangles is an equine respiratory tract infection causing fever, nasal discharge and swollen lymph nodes, particularly in foals and yearlings.

New Zealand Thoroughbred Racing said in a statement on Thursday the stable licensee had quarantined his stable and called in a vet.

There will be no changes to the NZ race schedule.

"All licence holders are reminded to be vigilant in checking the health status of horses under their care and also reminded to maintain sound biosecurity practices," NZ Thoroughbred Racing said.