The Auckland Regional Public Health Service said a young woman who went to the memorial at the Free Wesleyan Church in Favona on 15 September has since been diagnosed with measles.
A doctor with the service, William Rainger, said people who went to the memorial should be vigilant for symptoms of the highly infectious disease from today.
Dr Rainger said these include a high fever, runny nose, a cough and sore red eyes. A few days later a rash starts on the face and neck, and then spreads to the rest of the body.