Passengers on a Singapore Airlines flight may have been exposed to the highly infectious measles virus.
Auckland Regional Public Health Service issued an alert after a person on Flight SQ285 from Singapore last Thursday was found to have measles.
Passengers in rows 31 to 49 were closest to the measles case and are at highest risk, but anyone on the 11.45am flight should watch out for symptoms, said the health service, which is trying to contact people seated close to the patient.
"Anyone on the flight, around the flight gate or baggage claim at this time, could have been infected," said the health service.
Medical Officer of Health Dr Michael Hale said measles are easily transmitted from one person to another, even by just walking past the passenger with measles, or while sitting near them in the airport gate lounge," he said.
Hale said symptoms may appear tomorrow or over the next eight days.
The first symptoms are a fever, runny nose, cough and sore red eyes. After a few days a red blotchy rash develops.
Before the rash appears, measles is one of the most infectious airborne diseases.
"If anyone who may have been exposed knows they don't have immunity to measles they can be vaccinated, and that could prevent the symptoms developing," he said.
"The only way to protect from measles and the best way to avoid its complications is to be fully vaccinated.
"Anyone born before 1969 is likely to be immune to the disease without having had the vaccine."
One in 10 people who get measles need hospital treatment and the most serious cases can result in deafness or swelling of the brain.
Passengers feeling unwell should call their doctor before visiting the practice, or call Healthline on 0800 611 116 for advice.