New Zealander of the Year Dr Lance O'Sullivan storms stage at anti-vaccine film screening

A Northland doctor has turned up at the Kaitaia screening of a controversial anti-vaccine film, taking the stage to tell those in the audience the movie would "cause babies to die".

Dr Lance O'Sullivan, who was crowned New Zealander of the Year in 2014, bought a ticket to the screening of Vaxxed - from Cover-up to Catastrophe - but he hopped up before the film was screened to issue a stern warning.

The influential medical practitioner particularly took aim at those pushing the anti-vaccine agenda, saying they would be responsible for children's deaths should they continue to push the message of the film.

"I've come here not to watch the film, but to continue my battle and my challenge for my people and, importantly, for our children," he said.

"I come here with a lot of anger, because I am adamantly opposed to this. This idea of anti-immunisation has killed children around the world, and actually will continue to kill children whose parents are put off immunisation because of misinformation - misinformation based on lies, quite frankly.

"Fraudulent people for their own reasons have decided that they would put forward false information that actually causes harm to children. Your presence here will cause babies to die."

Dr O'Sullivan tried to discourage people from entering, and says two people left the screening.

Vaxxed explores the widely debunked theory of a link between the MMR vaccine and autism.

It's based on a 1998 study published in medical journal The Lancet. The paper was later found to be fraudulent.

The organiser of the Kaitaia screening, Tricia Cheel, says she was "flabbergasted" when Dr O'Sullivan "invaded the stage".

"He was obviously enraged and he was pointing his fingers. He ended up saying we would be responsible for the death of his vulnerable children. Very threatening behaviour," Ms Cheel said.

But she says she was more enraged to find he was turning people away.

"That to me was interfering with people's right to find out for themselves."

She believes doctors have been lied to.

"I can understand if he hasn't seen the movie he doesn't understand that a lot of what he's accepted as truth may be based on false information," she said.

But Dr O'Sullivan says it's the moviegoers who're being misinformed - and he's angry that health professionals and teachers were in attendance.

"They shouldn't be there quite frankly when these falsehoods of misinformation will cause harm to the children they are actually there to serve," Dr O'Sullivan said.

"These are people that are public servants and I think it's incompatible for them to have views on, are supporters of this anti-immunisation movement and work in these communities at the same time."

Northland DHB has been approached for comment but simply said it supports Dr O'Sullivan's position on vaccination.

An anti-vaccine advocate who attended the Kaitaia screening posted on Facebook saying Dr O'Sullivan also went outside after speaking, and tried to stop people entering the theatre.

He is also said to have performed a haka and "pointed his finger at people in a threatening way", according to NZME.

Organisers of the New Zealand screenings, WavesNZ, say: "If Dr. O'Sullivan had watched it he would know it's not anti-vaccine, rather pro safe-vaccine. So he's inaccurate in his interpretation of the movie he hasn't seen."

The film has been shown in eight locations around the country to more than 1200 people since its New Zealand premiere last month.

With a further seven events planned, organisers say they're now more determined than ever to continue showing the film.