Labor and the Greens have been forced to defend their decision to preference an anti-vaccination campaigner above the Coalition's candidate in a region that has one of the lowest child immunisation rates in the country.

Key points: ALP and the Greens preference each other second, but put the Nationals' Matthew Fraser in eighth and sixth place, respectively

ALP and the Greens preference each other second, but put the Nationals' Matthew Fraser in eighth and sixth place, respectively Labor says the preference flow is not ordered, but was done to make it easier for voters

Labor says the preference flow is not ordered, but was done to make it easier for voters Labor frontbencher Anthony Albanese has said the party often conducts "donkey votes" in seats where preference flows are not expected to affect the outcome

Tom Barnett from the Involuntary Medication Objectors Party, who is against mandatory vaccinations, is placed ahead of the Nationals' Matthew Fraser on the ALP's how-to-vote card for the House of Representatives in the seat of Richmond in northern NSW.

The region, which includes Byron Bay and Ballina, consistently has one of the worst immunisation rates for children under the age of five, according to the Australian Institute of Health and Welfare.

The ALP's how-to-vote card also lists independent Ray Karam as its sixth preference.

Last month, Mr Karam told the ABC he remains a member of a group called Universal Medicine, which the NSW Supreme Court has labelled a "socially harmful cult".

In February, the court ruled the group's founder, Serge Benhayon, preyed on cancer patients, indecently touched clients and vilified people with disabilities.

The Greens preference Ms Elliott second, Mr Barnett fourth, Mr Karam fifth and the Nationals' Mr Fraser sixth.

The National Party is preferencing Mr Karam ahead of the Labor candidate, but has put Mr Barnett last.

The Nationals put Ray Karam ahead of both Labor's Justine Elliot and the Greens' Michael Lyon, but put Tom Barnett last. ( ABC News: Bruce Mackenzie )

Labor holds the seat of Richmond on a margin of 4 per cent.

The party's how-to-vote cards place incumbent MP Justine Elliot first, followed by the Greens, with the rest following.

Labor insists it is not an ordered preference flow and says the card was allocated to make it simpler for voters to follow.

"We also want to make sure as many votes as possible are recorded as formal and this approach helps to minimise accidental informality by the voter," a Labor spokesperson said.

At least 15 of the ALP's how-to-vote cards follow a similar approach.

Opposition frontbencher Anthony Albanese told RN last week the Labor party often conducts so-called "donkey votes" in seats where preference flows are not expected to affect the outcome.

Sorry, this audio has expired Labor denies seeking preference deal with Clive Palmer

A donkey vote is where candidates are ranked based on the order they appear on the ballot paper.

Mr Albanese made the admission after being questioned over the ALP's decision to place Clive Palmer's United Australia Party second on how-to-vote cards in the Tasmanian seat of Franklin, where Labor is expected to finish first.

"Labor's preferences won't be counted in seat like Franklin so you make the how-to-vote as simple as possible … Certainly in the way how-to-votes are done, quite often that's done," Mr Albanese told the ABC.

A Greens spokesperson said preferences decisions are made by local branches. Greens NSW has been approached for comment.