There is concern the vaccine rollout is not reaching people using mental health and addiction services - people who were prioritised by the government for earlier access to the Pfizer jab.
Right now 37 percent of the eligible population is fully vaccinated; compared with 19 percent of people using mental health and addiction services.
And 71 percent of the eligible population is partially vaccinated versus 42 percent of this priority group.
Advocacy group Changing Minds chief experience officer Taimi Allan told Checkpoint there were many reasons for the low uptake.
She said health professionals outside of those direct mental health services "weren't that aware of the mental health issues being part of Group 3, and so their advocacy and their reach out to those groups were probably a little bit slow on the uptake".
Allan said it was good to see that 42 percent of the group had now received their first dose.
"I think that's due to the real efforts of some of our mental health services reaching out and using that manaakitanga to understand and validate some of the concerns that people have.
She said people with mental health and addiction issues "have not always been treated fairly when it comes to medication and coercion in our past".
"So there's some ... trepidation and timid responses about whether this is another part of coercion or what it actually means for them.
"There are a lot of people on some strong medications and there's some trepidation about what that might mean in terms of how it might contraindicate, so just being able to talk to people through some of the things that might be scary to them and give them enough information but really understand where those fears might be coming from based on their history."
She said some people would have had to take medication and injections, and it might have not always been an easy process.
"Needles can be equated as needles for people, and separating that out from something that might be beneficial to their physical health like the vaccination ... things that might have been coercive of the past is a really important conversation to be having really patiently with people."
She said statistics showed that people with mental health and addiction issues died 20-25 percent younger than the rest of the population.
"And it's not because of our mental health and addiction issues, but it's because of physical health concerns that can be overshadowed by our medical system just by not seeing things before it's too late. There is definitely a growing awareness ... but it's still largely an invisible health inequity in our society."
She said Changing Minds had resources to help people feel safe while getting the vaccine.