The measles outbreak has spread to Wellington, with a teenager admitted to hospital over the weekend.
The total number of cases of the highly infectious, but preventable disease for New Zealand this year is now more than 100, with most of them in Canterbury and Auckland.
A spokesperson for the Capital and Coast District Health Board said the teenager was visiting the region, and was now in a stable condition.
Wellington's regional public health medical officer Craig Thornley said it was now investigating who the teenager had been in contact with, and who may have been exposed to the disease.
This is the first confirmed case of measles in the Wellington region since the current outbreak.
Regional Public Health said the MMR (measles, mumps, rubella) vaccine given on-time was the best way to prevent measles.
Measles is a highly infectious viral illness that can lead to serious health complications - including infections of the lungs and brain - and is sometimes fatal. It is easily spread through breathing, coughing and sneezing, but can also spread before the infected person feels sick or shows symptoms.
Symptoms include a high fever, runny nose, cough and sore red eyes.
A rash also appears on the face and neck a few days later, and then spreads to the rest of the body.
Anyone who thought they had measles should call their doctor or Healthline before turning up to a waiting room.
In New Zealand, the MMR vaccine is routinely given to children at 15 months and four years old.
Those with measles can potentially infect up to 15 others if they are not immune and parents should also check their child has had the appropriate MMR vaccine.
Adults under 50 years who have not had even one MMR dose should also get their free vaccination from their GP.
Those over 50 are considered immune as the disease was widespread in childhood, according to the the public health service.
One MMR vaccine dose protected about 95 percent of the population, with a second dose protecting close to 99 percent.