A spike in measles cases this week is the worst since the outbreak started, Auckland Regional Public Health Service said.
In the past week, there has been 81 new cases.
ARPHS advised people to make sure they have had the MMR vaccination, pointing out in a tweet it's free for under 50 year olds.
"Protect yourself and protect others," they advised.
As of midday, the total number of cases in Auckland this year was 456.