Several cases of measles have been confirmed at the University of Auckland.
Hundreds of medical and science students could have come into contact with the highly infectious disease.
- Hawke's Bay baby diagnosed with measles after Auckland trip
- MMR vaccine eligibility widened as measles outbreak spreads
- Measles outbreak: Who is most at risk of catching the disease?
Students and staff have been told to be extra-vigilant for symptoms.
Experts say low immunisation rates among young adults are to blame. Dr Nikki Turner said vaccinations need to be monitored.
"It's not at the top of people's mind until they see measles," she told Newshub.
"Health care services need to start looking at recalling people without any records."
Dr Turner warns measles should never become normalised, and told Newshub the current outbreak shows no sign of slowing.
There are also fears outbreaks could become a threat for Pacific nations.
There have been 441 cases of measles confirmed across the country so far this year, with 369 of them in Auckland.