A man who brought measles into the country on a plane from China infected a baby in a medical waiting room in Auckland, health officials say.
Members of the baby's family then contracted the disease
The man also passed the disease on to another man on the flight, who ignored quarantine advice and visited SkyCity and Sugar Tree Apartments last month.
All those who were exposed at SkyCity have finished their quarantine period with no infections reported.
But the Auckland Medical Officer of Health Richard Hoskins said officials were working to contain an outbreak involving the baby and its family.
"So the person who flew in while they had measles also passed it on to one baby in an accident and medical clinic waiting room," he said.
"There are members of that baby's household who have now also got measles."
The baby spent a few days in hospital and was better now.
Health officials were also dealing with two other suspected cases not connected to the baby or the SkyCity scare.