Auckland's public health service is checking in with more than 2000 people who may have been exposed to measles as the number of confirmed cases climbs.
Since Sunday, a further six people have contracted the illness, taking the number of confirmed cases to 33.
Auckland Regional Public Health Service said a further 29 people were in quarantine and they were following up with more than 2000 people who might have been exposed to the disease.
Parents are being asked to make sure their children are immunised on time and also check their immunisation history.
The health service said the last time Auckland had an outbreak was in 2014.
It said the best protection against measles was to be vaccinated.
In Canterbury, 39 measles cases have been confirmed so far, and there were 12 confirmed cases in Bay of Plenty, and one case confirmed in Northland and another waiting on the test results.
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, ARPHS said.
Medical officer of health William Rainger said those with measles could potentially infect up to 15 others if they weren't immune.
Dr Rainger said parents should also check their child had the appropriate MMR vaccine.
Adults under 50 years who haven't 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 ARPHS.
One MMR vaccine dose protected about 95 per cent of the population, with a second dose protecting close to 99 per cent.