Parents should familiarise themselves with measles symptoms as children head back to school, the Auckland Regional Public Health Service (ARPHS) says.
Six new cases in Auckland were notified on Friday, taking the number of confirmed cases in the city this year to 27.
With the school holidays ending, the likelihood of interacting with an infected person increased, medical officer of health William Rainger said.
"People should be very aware of the symptoms of measles which starts with a fever and cough and runny nose and sore red eyes and then after three or four days arash appears on the face and then spreads to the body."
Those with measles could potentially infect up to 15 others if they weren't immune, he said.
Anyone who thought they had measles should call their doctor or Healthline before turning up to a waiting room.
Parents should check their child had the appropriate MMR vaccine, Dr Rainger said.
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.
It said one MMR vaccine dose protected about 95 percent of the population, with a second dose protecting close to 99 percent.
So far during the spate of measles cases, ARPHS has followed up over 1800 people who have been exposed to someone infectious with the virus, according to Dr Rainger.