District Health Boards across the country are starting to spread the message - as immunisation rates drop and the prevalence of certain diseases re-emerge.

Canterbury is dealing with 10 cases of measles, while 150 people in Auckland are also at risk of contracting it.

Waikato DHB interim chief executive Derek Wright told Mike Hosking vaccinations campaigns in the past have been too successful.

"We are seeing falling immunisation rates around the country at the moment."

"We have almost eradicated the diseases. So then a lot of people have stopped thinking about things like measles as being an issue."

He said 15 to 35-year-olds are the most likely to not be vaccinated and need to be the target group.

"They are the ones who haven't been vaccinated in the past and those are the ones we need to target because that's the next generation...the ones who are then going to vaccinate their kids."

Wright said while some people choose not to vaccinate, lots of other vaccinate late or just don't engage with vaccinations because they don't see the effects of those diseases.

The Ministry of Health has set a 95 per cent coverage target for all DHBs to achieve community immunity.

In the three months to December 2018 only one DHB, Auckland, achieved that target. The average of all 20 DHBs was 91.4 per cent.

The combined percentage of opt-outs from the National Immunisation Register (NIR) and declines of one or more vaccinations at age 8 months increased every year from 3.9 per cent in December 2015 to 5.3 per cent for the year to December 2018.