A case of whooping cough has been confirmed in the Nelson Marlborough region, and health officials there are warning of community transmission.
Te Whatu Ora Nelson and Marlborough announced the case on social media Friday evening.
"Although there is only one case confirmed, this case has caught the illness from another case, and it is therefore very likely to be spreading in the community and it is crucial for people to be vigilant," the post stated.
No further details about where exactly the case originated were given.
Three babies have died of whooping cough this year so far, Te Whatu Ora has said previously.
In a statement, Te Whatu Ora - Nelson Marlborough Chief Medical Officer of Health Dr Nick Baker said that whooping cough is most infectious in the first two weeks.
"Small infants frequently do not have the classical cough, apnoea and cyanotic episodes can be very dangerous."
The disease, also known as pertussis, can give people a bad cough that can make it difficult to breathe and often finishes with a whooping sound, dry-retching or a vomit.
It is particularly dangerous for babies and young children.
The disease often started with cold symptoms, like a runny nose and a mild cough, and Te Whatu Ora officials have urged anyone with those symptoms to stay away from new-born or unimmunised babies as much as possible.
New Zealand currently has record low rates of immunisation for children under four, with Māori children most impacted.