The Auckland Regional Public Health Service is warning passengers should be vigilant for symptoms of the highly-infectious disease.
The passenger departed Auckland for Nuku'alofa at 8.30am on Monday, returning at 12.30pm on Wednesday.
Medical Officer of Health Maria Poynter said passengers who were unsure about their immunity should check with their doctor or call Healthline for advice.
She says passengers not immunised, pregnant, living with a weakened immune system or under 12 months old should see their doctor urgently.
Measles symptoms include a high fever, runny nose, cough and sore red eyes.