Spending by the Ministry of Health on measles vaccine has almost doubled this year.
There have been almost 600 cases of measles around the country this year, with 90 people being hospitalised so far. The outbreak is the worst since 1997.
Public health director Mark Jacobs says $2.2 million has been spent so far this year on the MMR vaccine, compared to about $1.2 million last year.
The Auckland region bore the brunt with 80% of all cases.
Auckland also had a higher proportion of adults affected than children overall, which is not the pattern elsewhere.
The ministry urges anyone not fully immunised to see their doctor now.