Seventy-eight people are to be quarantined after coming in contact with measles

Health New Zealand's said it's reached out to 286 close contacts since the first case was confirmed earlier this month.

Ninety-percent of people unvaccinated that come in contact with measles will be infected.

Dr Bryan Betty said it's one of the most contagious diseases known to man.

He says Covid has, a reproduction number of two to three and influenza is one point three - so measles sitting at 12 to 18 is completely off the scale.