Australians will soon know whether an Indigenous voice will be enshrined in the constitution, as polls close across four states and the ACT.
Millions of voters attended 7000 polling booths across the nation on Saturday for the first referendum since 1999.
They were asked whether Aboriginal and Torres Strait Islanders should be recognised through a permanent, non-binding advisory body in the constitution that would be able to make representations to the government and parliament.
Polling has closed in NSW, Victoria, Tasmania, the ACT and South Australia, with Queensland, the Northern Territory and Western Australia to follow.
Four of the six states will need to vote in favour of the referendum for it to succeed on top of a majority of all Australia's voting 'yes'.
A three-three state tie will result in a 'no' result.
Prime Minister Anthony Albanese remained hopeful of a 'yes' outcome, despite published polls pointing to the 'no' vote succeeding.
Mr Albanese, who pledged the constitutional change in his 2022 post-election speech, said he had done everything possible to ensure a successful referendum.
"This is an opportunity for Australia to unite, to be strengthened by reaching out to our most vulnerable citizens," he said in his final pitch to voters on Saturday.
Mr Albanese said the 'no' campaign had "spoken about division while stoking it".
A Newspoll survey published in The Weekend Australian showed a three-point swing toward a 'yes' vote over the past week to 37 per cent.
With 57 per cent of surveyed voters saying they intended to vote 'no' as of Friday, a point down on the previous poll, the referendum would be lost if the poll results were reflected at the ballot box.
Six per cent of voters said they remained undecided.
Newspoll found there was not a single state where the 'yes' vote led.
Opposition Leader Peter Dutton said the proposed advisory body was "risky, unknown, divisive and permanent".
He told Seven's Sunrise program he thought the voice would just be another layer of bureaucracy.
"If I thought it was going to provide the practical outcomes in Indigenous communities, then it would be a different story."
Nationals leader David Littleproud said the prime minister had divided the country and healing would now need to take place.
"In terms of the result, no one should feel guilty about how they vote today or guilt about the result," he told the ABC.
Labor frontbencher Michelle Rowland said the government would accept the decision no matter the outcome, but closing the Indigenous wellbeing gap remained a priority.
"We took to the election a commitment to have this referendum in our first term, we are honouring that commitment," she told Sky News.
Prominent 'yes' campaigner Dean Parkin said any support for the voice would be seen as a step forward for Indigenous reconciliation.
"The votes that come in now ... represent the creation of a base of support by Australians from all walks of life in support of recognition, in support of a voice, and I believe in the support of Indigenous progress more generally," he told the ABC.
"And that is something that we are absolutely proud of having been part of creating through this campaign."
Peter Dutton says Australians don't have enough detail on how the voice to parliament will work.
About 6.1 million Australians voted early and 2.1 million eligible voters applied for a postal ballot, leaving around 9.2 million Australians to cast their votes on Saturday.
Electoral commissioner Tom Rogers said he had been shocked at the "nutty" conspiracy theories surrounding the vote, with Australia having one of the most transparent voting systems in the world.