Another case of measles has been reported on an international flight between Auckland and Sydney late last month.
The person departed Auckland on Air New Zealand Flight NZ711 just before 8pm on Friday, August 23.
They then returned from Sydney on Flight NZ108, which departed at around 7.50pm on Sunday, August 25 and landed in New Zealand at 12.15am on Monday, August 26.
The person reportedly did not know they had measles at the time.
Auckland Regional Public Health Service (ARPHS) medical officer of health Dr William Rainger said people who may have been in contact with that person should be vigilant for symptoms of the highly infectious disease.
"It can take 7-14 days to start experiencing symptoms and you are most at risk if you're not immune to measles, either because you haven't been vaccinated or you haven't had the disease previously," he said.
Anyone who was on the same flights, or in the airport departure or arrival areas around the same time as the person, should watch out for signs of measles.
If you were on either flight and are unsure whether you're immune to measles, talk to your doctor or call Healthline on 0800 611 116 for advice.
The alert comes as ARPHS figures released at 2pm today show there have been 812 confirmed cases of measles in Auckland this year.
A total of 561 of those cases have been in the Counties Manukau District Health Board area, with 141 in the Waitematā DHB and 110 in Auckland DHB.
The number of people infected with measles nationally soared to 963 yesterday, according to ESR figures.