A person with measles attended a recent movie screening in Rotorua, health officials say.
The latest case brings the total infected in the Bay of Plenty region in the past 12 months to 75, but there are fears they might have infected others.
They went and saw hit film Jumanji: The Next Level at 3:15pm on December 27 at the Reading Cinema, Dr Neil de Wet, Medical Officer of Health, said.
"Anyone who was at this screening may have been exposed to measles, and if under the age of 50 years and not up to date with their measles immunisations is at risk of getting measles."
Anyone who contracted the highly contagious disease probably wouldn't be showing any symptoms yet, but should from Friday. Early symptoms include fever, cough, runny nose and sore red eyes, which come a few days ahead of the rash.
"If you think you may have possible symptoms of measles, stay at home and phone your doctor to alert them so that they can make arrangements to assess you safely and without infecting others," said Dr de Wet.
"Please do not just turn up to your doctor or the emergency department without first phoning ahead, as you could infect others in the waiting room."
Measles cases across the country spiked last year - particularly in Auckland, which is believed to be the source of the deadly Samoan outbreak, which left 81 dead.
While no one has died from measles in New Zealand since the early 1990s, there is growing evidence the virus can can wipe out immunity from other diseases.
Jumanji: The Next Level has been a massive hit, knocking the latest Star Wars film off the top spot at the New Zealand box office and bringing in hundreds of millions of dollars in its first few weeks worldwide.
