Health services in Auckland are warning people to watch out for symptoms of measles after a woman visited supermarkets while infectious.
There have been five new cases of measles in Auckland, bringing the total number of notified cases in the city to nine.
Auckland Regional Public Health Service medical officer of health Dr William Rainger said most of the new cases were due to close household contact with an infected family member.
He said one new case was not linked.
Dr Rainger said a woman in her 40s had been isolated but she visited a Countdown supermarket when she was infectious. It was at Silverdale on Monday, 18 March.
She also visited another Countdown store in Orewa at 11am that morning, and Oliver's Cafe, also in that area.
On 20 March she visited a Four Square in Parakai.
Anyone who was not vaccinated against measles who was also at those locations could have been exposed to the virus, Dr Rainger said.
Symptoms include fever, a runny nose, cough or red eyes then a rash starts on the face a few days later, moving down the body.
"Please consult your general practice if you think you have been exposed to measles, or that you may have it. But phone first.
"Public health is tracing all household, work, social and other contacts of these cases to check their immunity, discuss quarantine and monitor the appearance of any symptoms, following standard public health procedures."
More cases possible after infected person travelled on plane from Melbourne
The Canterbury District Health Board is warning people who travelled to Christchurch from Melbourne on a flight earlier this month may have been exposed to measles.
The DHB said a passenger arriving in Christchurch from Melbourne on 19 March was confirmed as having measles, adding to the cumulative total of 35 confirmed cases for Canterbury.
The person travelled while infectious and the DHB's community and public health team wanted to alert all passengers and crew on the flight that they could have been exposed to measles
The flight, Virgin Australia Flight VA99, left Melbourne at 6.35pm local time and arrived in Christchurch at 11.35pm New Zealand time.
The DHB said anyone who travelled on this flight who was not sure they had been fully immunised should check their immunisation status with their GP.
Canterbury medical officer of health Alistair Humphrey said people from the flight who may have measles should stay in self-imposed isolation from Tuesday 26 March until Tuesday 2 April - seven to 14 days after contact.