The Australian Medical Association says Labor and the Greens are sending the wrong message by preferencing an anti-vax campaigner above the Coalition candidate in an area with one of the lowest rates of child immunisation in the country.

In the northern NSW electorate of Richmond, Labor and the Greens' how-to-vote cards instruct their supporters to put Tom Barnett of the Involuntary Medications Objectors Party (IMOP) ahead of the National Party candidate.

The IMOP is opposed to vaccinations and water fluoridation.

Facebook

AMA NSW president Dr Kean-Seng Lim told SBS News the parties had prioritised political expediency over public health.

"This sends a message to the community that important public health measures like vaccination don't matter," he said.

While Labor and the Greens downplayed the importance of the preferences, Dr Lim said it gave a "goose" like Mr Barnett a level of credibility he did not deserve.

Doctors appeal to Hollywood star

The electorate includes Mullumbimby, near Byron Bay, where less than half of two-year-olds were vaccinated, in the latest figures from the Australian Institute of Health and Welfare.

Dr Lim last week called on Avengers actor Chris Hemsworth, who lives in Byron Bay, to make a stand against the anti-vaccination campaigner.

"The Avengers are there to save the world and vaccinations are truly one of the ways to do it," Dr Lim said.

AAP

Labor's Jim Chalmers said on Wednesday the how-to-vote cards were simply designed to make it easier for voters.

"What they try to do is they work out who their key preference arrangements are, and then they try to make the how-to-vote card as simple as possible and that's what we've done," he told ABC News Breakfast.

He dismissed suggestions the move would send the wrong message about the party's stance on vaccination.

"It is a crucial thing that we get our kids vaccinated."

READ MORE New Zealand prepares for major measles outbreak with free vaccinations

Greens Leader Richard Di Natale, who has been critical of the Liberal Party's preference deal with mining magnate Clive Palmer, also downplayed the importance of preferences in the Richmond electorate.

AAP

"Well those preferences won't be distributed, they're way down the bottom of the ticket so those preferences will go to the Labor Party," Senator Di Natale told ABC radio.

Senator Di Natale, who is a qualified doctor, brushed off claims he was being hypocritical.

"It was a decision made by a local group ... no one has been more supportive and has been a stronger advocate of public evidenced-based measures."