Official and independent information must be given to the public if they're going to make a proper decision on euthanasia, an expert on assisted dying says.
Politicians on Wednesday voted to put Act leader David Seymour's contentious End of Life Choice Bill to a referendum at next year's election.
It would be held alongside a separate plebiscite on legalising recreational cannabis.
The euthanasia legislation still has to clear a third-and-final reading next month, but that looks fairly likely, meaning there will soon be public campaigns on both sides of the debate.
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University of Victoria research fellow Jessica Young led a study looking at the polling of attitudes towards euthanasia over the past two decades and says sentiment has been consistently in favour over that time.
Since 2002, support in every poll about assisted dying has hovered between 63 per cent and 82 per cent, averaging out to about 68.3 per cent for.
Opposition has averaged out to 14.9 per cent.
The euthanasia debate doesn't cut across demographics like other social issues, Young says. It shows factors such as gender and age don't appear to be indicators of how people will vote.
More educated voters are more likely to oppose assisted dying, according to the research, while rural voters are also more likely to support it. Support across people backing all major political parties is reasonably high.
"There's really broad support. There's no one typical supporter. Which is what makes [one] think there will be broad support when it comes to the referendum," Young says.
Campaigning around the referendum is likely to be fierce and emotional, but Young said it was unlikely to swing support enough to see the plebiscite voted down.
The referendum question, however, will only ask voters if they support the End of Life Choice Bill – not euthanasia itself.
Young said that made it crucial for the public to be properly informed.
The Prime Minister's Chief Science Adviser, Juliet Gerrard, is currently coming up with a summary of evidence to give to the public ahead of the cannabis referendum.
The same thing needed to happen with euthanasia, Young said.
"The information shouldn't be coming from lobby groups," she said.
"Really balanced information is going to be essential. It's a really complex piece of legislation."
But Deputy Prime Minister Winston Peters – whose New Zealand First party has forced the referendum – on Thursday said it was up to the media to inform the public.
"They've got the brains, they've got the intelligence, they've got the experience. You make sure they've got the information and they'll be fine," he told reporters.
Seymour is open to an independent source of information.
"It's possible that there may be a role for an independent source to debunk the fear, uncertainty and doubt campaign," he said.
During the Select Committee phase of the bill, a record 39,000 groups and people made submissions, the vast majority against.
Submissions are currently being heard on a bill that would lay out the rules around advertising for any referendums next year, with Justice Minister Andrew Little on Thursday arguing the rule changes should ensure the public are properly informed.