Hundreds of people in Auckland could have been exposed to the measles virus, after a person ignored medical instructions to go into quarantine.

The Auckland Regional Public Health Service has issued a measles alert for Sky City Casino and a central city apartment building.

The person contracted measles from an infected passenger on a China Southern Airlines flight that arrived into Auckland last month.

Despite being asked to go into quarantine, the person visited the Sky City Casino and the Sugar Tree Apartments.

Anyone who visited the casino between 9.45pm and midnight last Tuesday, and used the lifts and common areas at the Sugar Tree Apartments on Union Street between Tuesday and Saturday last week could have been infected.

They're being asked to go into quarantine for at least ten days.