Health officials are urging anyone under the age of 45 to check they have been vaccinated against measles, with 10 confirmed cases of the disease in Hawke's Bay since June.
Medical Officer of Health Caroline McElnay urged anyone under 45 who had not already had the measles, mumps and rubella (MMR) vaccine to have it.
She said young adults were particularly at risk because the uptake of the vaccine was not as good in that age group as it is now.
"The only way to be protected against this particularly nasty disease is to be vaccinated."
Anyone born before 1969 or who had had two doses of the vaccine could reasonably assume they were already immune. Two doses of the MMR vaccine were needed for full protection. People could check their vaccination history with their GP. The vaccine is free for all New Zealanders.
Measles is spread by tiny droplets in the air and can be spread easily to anyone nearby.
The first symptoms include a fever, cough, runny nose, sore and watery pink eyes and sometimes small white spots on the back inner cheek of the mouth. After three days, a blotchy rash, usually starting on the face, moves up over the head and down the body. There is no direct cure and complications can include pneumonia and diarrhoea.
Anyone who suspects they have measles should phone their GP or call Healthline on 0800 611 116 for advice. It is important to call first before seeing a doctor because measles is highly infectious, and people can infect others in the waiting room.