Passengers on two domestic flights and one international flight have been exposed to the measles, health authorities warn.
A person who had the illness but who did not realise it would have been infectious travelled on Air New Zealand flights from Auckland to Christchurch and back earlier this month, the Auckland Regional Public Health Service said.
In addition, a person with measles on a Singapore Airlines flight to Auckland was also infectious at the time of travel.
It can take up to two weeks for someone with measles to start showing symptoms.
Anyone on the flights who may have caught measles could be starting to feel unwell in the next week, if they're not already, Medical Officer of Health Dr Richard Hoskins said.
Any passengers with concern should contact their GP, or Healthline on 0800 611 116.
Flights affected:
* Air New Zealand flight NZ501 from Auckland to Christchurch, departing 6.50am on March 2
* Air New Zealand flight NZ548 from Christchurch to Auckland, departing 6.55pm on March 4
* Singapore Airlines flight SQ285 from Singapore to Auckland, departing March 4