A measles alert has been issued for various locations in central Auckland and Newmarket.
Medical Officer of Health Michael Hale says people who have visited the affected areas at the specified times are likely to be exposed, and if they are not immune could get measles.
Dr Hale warns those infected will experience symptoms from seven days after exposure. Symptoms include fever, a runny nose, cough and sore, red eyes.
After several days a red, blotchy rash will develop on the face and spread to the rest of the body.
"People who are feeling unwell and have visited these locations at the times suggested should immediately telephone their doctor or Healthline on 0800 611 116 for advice," says Dr Hale. "It is very important to phone in advance because measles is highly infectious and you could infect other people in the medical waiting room."
Measles is infectious before the rash appears and is easily transmitted.
Those who have had two doses of the MMR vaccine, or have had previous measles illness or were born before 1969 are considered immune.