Cases of measles have now been reported in Northland and Nelson following an outbreak in Waikato.
Waikato has 22 cases confirmed so far, and 12 other possible cases.
Cases have been recorded at Morrinsville College and Fairfield College, with students who aren't vaccinated being told to stay away until next Monday.
Northland District Health Board has had four confirmed cases and one unconfirmed.
One person is believed to have caught the virus at a kapa haka event in Waikato and then returned home.
Nelson District Health Board said it believed one teenage girl was infected after visiting Hamilton, but nobody else in the area was considered at risk.