Anti-vax GPs are hindering the rollout in our least vaccinated region, Northland, where an essential worker has returned a weak positive for Covid-19.
As of Sunday night, just 67 percent of people in the region had one dose of the vaccine and 42 percent were fully vaccinated.
This week, the District Health Board has also confirmed two of 34 general practices in Te Tai Tokerau do not support Covid-19 vaccination.
One Whangārei GP - whose registration was renewed in March - has spoken online about his anti-vaccination beliefs.
Dr Damian Wojcik's video, posted in May, is 20 minutes long.
In it, he says: "I am taking the unprecedented step of speaking publicly, along with a group of medical colleagues, regarding my deep concerns about the Covid-19 vaccine rollout to all New Zealanders.
Wojcik declined to talk to RNZ this week.
His practice, Northland Environmental Health, is part of the Mahitahi Hauora primary health enterprise of GP clinics.
Mahitahi Hauora medical director Grahame Jelley told RNZ there was "no place" for anti-vaccination messages in health practice, but he did not comment on specific GPs.
Northland DHB chief executive Dr Nick Chamberlain has briefed the board on the region's vaccination difficulties.
He said the region had hit a "bigger brick wall than the rest of the country" in the last month, and there was capacity for 16,000 vaccinations per week but only 7000 to 8000 people had been coming to get them.
"There's misinformation ... that it was developed too fast and yet the technology's been in development since SARS in 2003 and it's been tweaked."
Chamberlain said vaccine opposition was a problem in Te Tai Tokerau before Covid-19 but it was now worse.
"The adverse events are really openly reported on this, and they're very very low. So generally the misinformation, I think, has probably driven even more people towards an anti-vax position than before."
Royal New Zealand College of General Practitioners medical director Dr Bryan Betty said a "very small number" of GPs opposed vaccinations.
But he said "the fact they have Dr in front of their names gives them undue influence" and it can be "very very hard" for patients to determine fact from falsehood.
"Doctors who take this approach have undue influence in the system and it really does worry me when they are promoting views that sound 'semi-science'."
University of Auckland research published in 2018 said doctors were the most trusted health professionals for vaccine information, and they had a "crucial" impact on parents deciding whether to immunise their children.
Te Herenga Waka Psychology professor Marc Wilson is concerned anti-vax GPs are undermining the good work of the vast majority.
"There's also the risk of people who are hesitant or on the fence using this as evidence to justify not taking the vaccine."
The New Zealand Medical Council has taken a strong stance against anti-vax messaging from health practitioners, but chair Dr Curtis Walker (Whakatōhea, Ngāti Porou) could not comment if individuals were under investigation.
The council can refer matters to the Professional Conduct Committee, which can lay charges.
The Health Practitioners Disciplinary Tribunal could not confirm whether any charges had been laid against any health practitioners for anti-vaccine misinformation.