Health authorities have contacted about 1000 people as they try to stem a measles outbreak.
Two new cases have brought the tally to 22 on Monday. Of those, 16 are in Auckland, four in Christchurch and two in Wellington.
Health authorities are warning parents to keep their children away from schools where measles cases have been reported, if they have not been vaccinated against the disease.
Schools and health authorities have the power to force people to stay off work or keep their children away from school for two weeks if they will not do so voluntarily.
The Ministry of Health says if people who may have been in contact with measles carriers are traced early enough, they can be vaccinated.
Of the 22 confirmed cases, seven patients are aged under 10 and three people have needed hospital treatment.