A case of measles has been confirmed in Manawatu, the first since 2011.
The MidCentral District Health Board's medical officer of health, Dr Rob Weir, said people close to the infected person who were not vaccinated or immune to measles have been advised to stay home for two weeks.
He said measles was highly infectious and spread through breathing, coughing and sneezing.
Symptoms include a fever, runny nose, cough and sore red eyes, with a rash after a few days.
There have been three other recent cases across the country: one in Auckland involving a man in his thirties, and two in Christchurch involving preschoolers.
The DHB has not revealed whether the person might have come into contact with people who were unaware they were at risk of being infected.