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.