Three people in Wellington have contracted measles after a family holiday in Bali last month.
The regional public health authority said it was notified at the weekend, but is confident nobody else on the flight has been infected.
A Wellington medical officer of health, Annette Nesdale, said it again highlights the need for people to make sure they are immunised, because the disease is so infectious.
"People are infectious for five days before the rash comes out, and until five days after the rash.
"So whenever anyone's got measles and public health is working with them to stop the spread in the community, those people are in, what we call, 'home isolation'."
Ms Nesdale said a warning has been sent to local schools about the illness.