Autism New Zealand is worried the film Vaxxed legitimises false claims linking vaccinations to autism.
Northland doctor and 2014 New Zealander of the year Lance O'Sullivan's protest at a Kaitaia screening of the film has reignited debate.
1 NEWS has been contacted by anti-vaccination campaigners convinced their children have suffered from vaccine damage.
But experts say they're misinformed.
"Look, it's very concerning. I guess it's good people trying to get information. But at the end of the day it's got to be balanced, so again, the evidence suggests there is no link between vaccines and autism," said Dane Dougan of Austism New Zealand.
Meanwhile Dr O'Sullivan is now calling for vaccinations to be compulsory.
"We know that immunisation saves lives. I've had to hold the bodies of children who are ravaged by diseases that are preventable from immunisations, and try to save their lives," he said.
Dr O'Sullivan says health and community workers should not have been at the screening, and the Northland District Health Board chief executive, Nick Chamberlain, agrees those working with vulnerable children should be focusing on evidence.
"Even though I support hugely informed choice, when it's misinformed choice that's occurring I think we have got to step in," Mr Chamberlain said.