Health authorities are urging people in Northland and central Otago to be on the look out for measles symptoms

Three new cases were confirmed in Northland last night - bringing the total number of cases in the region to nine.

Health New Zealand says they're all previously close contacts of existing cases.

However, it says one was only identified after becoming infectious - meaning they may have spread the illness without realising it.

It's working to trace new exposure locations.

There's one unrelated case in Queenstown which was reported on Monday.

People in the Northland, Queenstown and Cromwell communities should monitor for symptoms.