The measles outbreak is now suspected to have spread to Northland as the number of cases in Auckland and Waikato continues to climb.
A three-year-old child who attended day care while in the infectious period has been identified with suspected measles, Northland District Health Board (DHB) medical officer of health Dr Clair Mills said.
The child, who was recovering at home, may have contracted the virus while visiting Auckland, where the virus originated.
"We are working with the child care centre, parents and general practice in the Ruakaka area to contain the spread of this disease and are in the process of identifying contacts and offering immunisation."
People who had not been immunised who had been in contact with the child would be asked to stay isolated at home for 14 days, she said.
There have now been 105 cases of measles in the Auckland region since the outbreak began in May, seven of which have required hospitalisation. Six people who have been in contact with those infected are in quarantine.
Seventeen cases have been confirmed in Waikato and a further eight people are suspected.
An Environmental Science and Research spokeswoman said the cases in Waikato had the same genotype as the Auckland cases, indicating they had spread from there.
A 17-year-old girl is also confirmed to have measles in Taupo, she said.
The Ministry of Health said common symptoms of measles included a runny nose, cough, sore eyes and fever, followed by a raised red rash that started on the face and moved to cover the rest of the body.
Anyone showing such symptoms should immediately telephone their doctor or Healthline on 0800 611 116, for advice.