More than 1000 adults and children may have to be quarantined after a child with the measles attended a Seventh Day Adventist holiday camp in Rotorua.
Photo: RNZ /Dom Thomas
The Auckland Regional Public Heath Service is working to locate the 1200 people who may have been infected.
Clinical director Julia Peters said the child was infectious on 5 and 6 October.
She said anyone who was at the Tui Ridge Park camp may be developing the measles now.
"So in the early stages of measles it can seem like any other illness, you've got a high fever, a runny nose, cough, sore eyes," she said.
"That goes on for about four or five days and then you develop the rash..."
Dr Peters said those who were not immune to the measles would have to remain at home in quarantine until the end of 20 October.
The camp was attended by people from Auckland, Hamilton, Lower Hutt, Wellington, Tauranga, Rotorua and Manawatū.
Those regional health services have been notified.
Children there were aged between four and 15.