Matt Qvortrup, expert who predicted Brexit says Voice to Parliament will fail without Peter Dutton's support

Now, he's warning the Voice to Parliament campaign: get bipartisan backing and go early, or you'll be crushed.

Australian National University political scientist Matt Qvortrup warns the result would be "on a knife edge" even with the Coalition's support, and the "yes" campaign's chances will rapidly deteriorate the longer a vote is delayed.

The Coalition is yet to reveal its stance, leader Peter Dutton saying it will wait until more detail is put to the public.

But another experienced pollster says Dutton opposing the Voice, backed by a progressive millennial voter bloc which is "increasingly dominating the political landscape", would be self-destructive.

He says young voters will drive the "yes" campaign home, pointing to the marriage equality vote as a sign of things to come.

Early polling suggests overwhelming support for a First Nations' Voice, but most voters reported having heard very little or nothing about the proposal itself.

And with Prime Minister Anthony Albanese staking much of his political capital on the vote, Labor is undergoing an extensive legal and community consultation process in a bid to assuage voters' concerns.

Albanese insisted he is "very confident" that will be enough come voting time.

"We know that you'll get better practical outcomes, like any other endeavour, when you actually consult people who are directly affected," he said on Wednesday.

But Qvortrup, who also correctly predicted Scotland's rejection of independence in 2014, says his model shows the "yes" campaign losing by at least 8 per cent if Dutton opposes it, a clearer margin than the doomed 1999 republic referendum.

"If I were to advise Mr Albanese, or whoever is in favour of this, I would say: hold it as soon as possible," Qvortrup tells The Canberra Times.

"The more information you put out there, the more people will say: I'm not sure about this, I don't really understand this."

History proves strong early backing does not always translate at the ballot box.

Morgan polling showed support for a republic hovering at 52 per cent a year from the vote, with 37 per cent opposed. That splintered to 45 per cent by the time Australians cast their ballots.

Former prime minister Robert Menzies' 1951 attempt to ban the Communist Party fell apart from even loftier heights. Polling suggested nearly 80 per cent backed the idea initially, but just 49.4 per cent ultimately voted for it.

Qvortrup says that's typical of referenda campaigns, which tend to begin with a "yes" camp well ahead, before being pegged back as two-thirds of undecideds break against it.

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He warns results have "nothing to do with the question", and are largely driven by external factors.

"It would be good if democracy could be people pondering and deliberating carefully about the pros and cons of particular issues," he says.

"But basically people use them as a way to give the government a kicking."

His modelling suggests bipartisan support, consigning political opposition to fringe parties, generally offers an 8 per cent boost to the "yes" campaign.

But compulsory voting tends to reduce the Yes vote by around 10 per cent, with voters often resentful at being forced to cast a ballot on an issue they either do not understand or care about.

"The higher the turn out, the higher the 'no' vote," Qvortrup says.

"[And] where you have compulsory voting, you get a lot of people who feel they don't really want to vote, they're upset that they have to vote, they feel they've been dragged out."

Given roughly 1.6 per cent is also shaved off for each year a government is in power, Qvortrup's model predicts a "yes" vote backed by both major parties would enjoy around 52.5 per cent of the vote today.

It would be neck-and-neck if it was held next year, and a minority if held just before a 2025 federal election, he says. Without the Coalition's backing, it would suffer a crushing defeat regardless of when Australians vote.

"You need to get bipartisan support for this, because then you can muddle through ... [but] it would be very much on a knife edge even if they get [it]," he says.

"Far be it for me to advise people what to do, but I would say: if you don't want a bloody nose halfway through your premiership, then you might find a way of getting out of this one."

Getting out of its predicament would mean Labor finding a way to convince voters the Voice was not "Canberra dictating things", Qvortrup says.

He cited Ireland, where regular voters are convened in citizens assemblies' before holding a straw poll, as a potential model.

"You need to wash your hands of it, make it unpolitical. Politics is about friends and enemies. You want to take the politics out of this by making it fairly pragmatic," he says.

Just 13 of the 44 referenda held have gained more than over 50 per cent of the vote, and only eight have secured the double majority - backing from most voters and most states - required to pass the proposal.

But RedBridge director Kos Samaras insists Australia is a "vastly different" country to the one which rejected previous referenda, with voters increasingly opting for "more compassionate" politics.

Samaras, who conducted polling for Climate 200 before the May election, believes the Voice will pass after the Coalition backs it for "strategic reasons".

RedBridge's surveys in Victoria, centring on First Nations issues like Treaty, also show voters in suburban areas back "a more robust approach to Aboriginal rights".

"[And] millennials are increasingly dominating the political landscape. They're overwhelmingly the most progressive generation in this country's history across a whole range of social issues," Samaras says.

"That includes those who would consider themselves economically conservative."

Millennials accounted for just 18 per cent of Victoria's enrolled voters in 2012. That now stands at 36 per cent, a trend reflected across the board.

And given the Coalition is already struggling to woo the cohort, Samaras believes the "pragmatic" Dutton will see benefit in backing the Voice.

"The danger is if the 'no' camp is able to confuse voters, and create doubt and all sorts of confusion," he says.

"The flip side is that if Dutton goes into that space, he'll blow a much wider hole with the millennial camp ... The long-term political consequences for conservatives in this country would be dire."

While no Australian referendum has succeeded in half a century, the 2017 marriage equality plebiscite was a pseudo-referendum of sorts.

Then, the "no" camp stoked fears of change and placed the issue in a broader culture war, former prime minister Tony Abbott urging Australians to vote against it and "stop political correctness in its tracks".

But after a record surge in voter enrollments, mainly of young people, the "no" campaign was trounced 61-39.

"That's your most recent reference point," Samaras says.

"Fast forward, we've got five years of further enrollment of young people and further decline of boomers and older [voters]."