Immunisation levels at Nelson Marlborough District Health Board (DHB) are below target because of the choices made by parents, the board's chair says.
An annual performance review shows access to initial cancer treatments has improved over the year, but childhood immunisation rates are below target.
The board was particularly below target among Māori and Pasifika.
DHB chair Jenny Black said it was an area in which the board struggled to achieve its goals.
"It's not about people not knowing about immunisation, it's about people declining immunisation.
"It's always been a struggle for Nelson Marlborough to meet that, so they're people who are choosing not to be immunised."
However, Ms Black credited hospital staff for helping improve targets for access to initial cancer treatments, many of which were administered by larger hospitals outside the region.
However, the 2016-2017 summary also showed 85 percent of people receive their first cancer treatment within 62 days of referral.
Access to elective surgery had also improved along with waiting times in emergency departments.