The measles outbreak in Waikato is continuing to spread, with more than 50 confirmed cases.
The Waikato District Health Board is investigating a further 12 potential cases and is asking students at Morrinsville Intermediate and Morrinsville David Street schools to stay home in quarantine if they're not immunised.
The medical officer of health, Richard Vipond, said the outbreak had been going for more than 13 weeks and 10 people had been hospitalised since it began.
The number of people catching measles continued to increase, he said.
This was a serious outbreak and it was important for parents to check their own immunity status, as well as their children's.
Measles is a serious disease and the symptoms can take between eight and 21 days to appear.