The 2014 New Zealander of the Year Dr Lance O'Sullivan interrupted a controversial screening for anti-vaccine documentary Vaxxed in Kaitaia last night with a passionate speech telling the organisers they are contributing to deaths, before performing a defiant haka.

Screenings of Vaxxed across the country, including Whangarei and Kaitaia, had been kept secret, with organiser group WavesNZ notifying ticket holders of the venues just a few hours in advance.

Dr O'Sullivan was invited to watch along with a number of other health professionals, but took the chance to step on to the stage and share his views on the topic.

He said there is absolutely no evidence vaccines cause autism and he is concerned for his community because immunisation is safe and extremely important for children.

"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 ... that's because I am adamantly opposed to this because this position is, 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."

"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 criticised on social media

Dr O'Sullivan has since been criticised for his actions on social media, with The Warning against Vaccination Expectation group, who posted "Trina Cheel [the event organiser] was verbally attacked, bullied and threatened by Lance O'Sullivan at the Vaxxed screening last night.

"Dr Lance O'Sullivan came into the cinema under false pretences of watching the movie."

Laurence Bacchus, who works with intellectually handicapped and high needs people at Hawke's Bay's Hohepa Services, wrote that Dr O'Sullivan is a "pharma whore" and a "disgrace to his profession", before adding "New Zealander of the year my arse!"

Dr O'Sullivan denied that he attended the event under false pretences, saying he was invited to attend and simply got on the stage to give his view.

A poster for the movie 'Vaxxed'. Source: Supplied

He was named New Zealander of the Year in 2014 for his work in public healthcare - the same year he was also named by Readers Digest as the second most-trusted New Zealander, behind Victoria's Cross winner Willie Apiata.

The film Vaxxed is a 2016 American film from anti-vaccination activists Del Bigtree and Andrew Wakefield.