South Australia Opposition leader David Speirs says he thinks Prime Minister Anthony Albanese should resign if the final result of the referendum is a resounding No.

"I think the damage he has done to our country and to the very fabric of what it means to be Australian is quite frankly heartbreaking," he said to Australian reporters.

"It'll be up to the Prime Minister and the federal Labor Party tomorrow to make a call on what he does now - but I think he should resign, he said.

Tiffanie Turnbull
BBC News, Darwin/Garramilla

Before the polls even closed in the Northern Territory, the referendum was all over.

We watched the ABC declare its defeat in an empty room full of yes signs.

It'll probably be an hour before volunteers and campaigners start trickling in here, to the official Yes 'party' - if they do at all.

But it's already clear this evening will not be a celebration.

Image source, EPA

Independent senator and the leader of the Indigenous 'Progressive No' camp Lidia Thorpe, told Australian Broadcasting Corporation that the results coming through so far are in line with what she expected to see.

"I'm not surprised that we've got No votes coming out strongly, because people don't either know what it is about or that in terms of the Blak Sovereign Movement, we don't want to go into the constitution, and I think we have been loud and clear about that and we have certainly got a lot of support," she said.

"This country going to the referendum to decide on our destiny was the wrong thing to do, and that's where we as Aboriginal people need to come together and make those decisions for ourselves. That's what a treaty can do. That's what truth telling can do."

"You don't need a referendum for a treaty. And you don't need a referendum for extra senate seats in the Parliament."

ABC has said that South Australia is the fourth state to vote No - meaning that the referendum has failed.

With 12.4% of the vote counted, the Australian broadcaster says it is clear that Yes will not be able to obtain a majority in the state of Tasmania.

They spoke to some people who voted no in Tasmania. One of them said: "I voted no because I don't think we should put a line between us and them. We are all one people."

Another said: "It's one for all and all for one in Australia. That's why I voted no."

In the Australian Capital Territory, 2.6 percent of the vote has been counted, and Yes has a clear majority, the ABC projects.

Australia's most populous state New South Wales, which has Sydney as its capital, has been projected to vote no according to the Australian Broadcasting Corporation.

Image source, Getty Images

Election officers have started tallying votes in states where polling has closed.

A partial tally by the National Electoral Commission, based on 1,394 of 8,253 total precincts, shows No leading Yes with 58.04% versus 41.96%.

Simon Atkinson
Australia producer, BBC News

Rob Muller is is in favour of recognising Indigenous people in the constitution, but objects to the Indigenous advisory body.

“They’re basically asking two questions. Do we want to recognise them, and if we do it's a Voice... but they're providing space for one answer."

“I don't know why they didn't put recognition in legislation and see how it all works, then maybe later on try to increase it to something else."

He said he feared the impact the result might have. “After all this, it's going to take quite a while to heal.

"It worries me that it is going to create a lot of division and I think people are not going to forget it very quickly.”

Tiffanie Turnbull
Reporting from Darwin

At the heart of the Voice debate, is the Northern Territory.

Almost a third of its population is Indigenous. The Uluru Statement from the Heart - which calls for the Voice - was written here. And many Aboriginal communities which advocates say the reform is designed to help are here.

But when people who live in NT go to the polls today, their vote will count for less than other Australians.

Australia’s referendum rules require a double majority for them to pass - that means a majority of voters nationwide must write yes, but also that majority support in four of Australia’s six states is needed.

And that second metric excludes the NT and the Australian Capital Territory.

Though they have much smaller populations than the states, a lot of people who live here say it leaves them feeling like second class citizens - and in the NT’s case, suppresses the voices of many people who this debate is about.

Tiffanie Turnbull
Reporting from Darwin/Larrikia Country

I just spoke to one voter in Darwin who said she had been in two minds "because I didn't really understand the process".

After speaking to a Yes campaigner however, Anna Sarmento said it was the obvious choice for anyone who wanted positive outcomes for Indigenous people.

She pointed out that in the Northern Territory - where most government intervention occurs -more than 30% of the population is Indigenous.

"We need more representation and it should have been done long, long time ago.

"There's all sorts of [bad policy] happening which these people have no control over. Because they don't have that representation."

Across the country, polling booths were open from 0800-1800 but Australia is a big place, so it has three separate time zones.

South Australia, Queensland, the Northern Territory and Western Australia are still voting.There are also votes coming in from Australia’s offshore territories.

Voting is now finished in the most populous states of New South Wales and Victoria, as well as Tasmania and the Australian Capital Territory.

The referendum needs a majority of the national vote and a majority of states approving to succeed.

There's less than 10 minutes untill polls close. We can expect results to start flowing in soon after - so stay with us.

Image source, Reuters

In a final message to voters, Nationals leader David Littleproud told the ABC that his party would not be pushing to legislate the Voice to Parliament, if today’s referendum fails.

Littleproud said voters should not feel “guilted” about the result, calling for the “democratically determined position that the Australian people will make” to be respected.

"We have always had a longstanding view, if this referendum was about constitutional recognition and that alone, we would have supported it. That would have been a unifying moment."

And addressing the media in Perth, Western Australian Liberal Senator Michaelia Cash doubled down on the Voice as a “risky” proposal.

“If the Voice does get up, it’s risky, it’s unknown, it’s permanent, but more than that, regardless of the outcome tonight, the one thing Mr Albanese has done is divide this nation.”

Cash also said the Opposition would work to achieve better outcomes for Indigenous Australians by undertaking a review of wasteful government spending.

Hannah Ritchie
Reporting from Melbourne/Naarm

Throughout this campaign, tens of thousands of Yes volunteers have crossed the country to have "face-to-face" conversations with voters, hoping to cut through what has been a noisy - and often acrid - debate.

"Our pathway to winning has always been a field strategy," says Larissa Baldwin-Roberts, who leads the activist group GetUp.

"The only way you can persuade people is to have a values-based conversation...But that's an incredibly labour intensive thing to do."

The Widjabul Wia-bul woman and other Voice advocates will be hoping that the people power being deployed by Yes has reached enough undecided voters to turn around months of polling results that are suggesting a sizeable No victory.

Simon Atkinson
Australia producer, BBC News

One of the architects of the Voice and most prominent faces of the Yes campaign is Noel Pearson.

The Guugu Yimidhirr man is also an influential figure in Australian Indigenous affairs.

The Cape York Partnership he founded tries to empower and improve the lives of First Nations peoples in the north of Queensland, with a particular focus on education.

When we met in Brisbane last week to film an interview for our coverage of this referendum, he said Australia was "going through a process of trying to address the legacy of British colonisation" and that the disadvantage among Aboriginal and Torres Strait Islander communities was "still egregious".

The official No campaign says the Voice is a "radical" proposal that will "permanently divide" the country by giving First Nations people greater rights than other Australians.

It also argues the Voice is "a leap into the unknown" because it hasn't been "road-tested", pointing to the lack of detail about how it would operate.

Leading constitutional experts say the Voice does not confer special rights on anyone. And if the reform passes it would be up to parliament to design the Voice, giving lawmakers the power to change it over time.

Grassroots groups - such as the Indigenous-led Blak sovereign movement - have spoken out against the Voice for other reasons though. Their argument is that it would be "another powerless advisory body" and that treaty negotiations should be prioritised instead.

Image source, Getty Images

Simon Atkinson
Australia producer, BBC News

In Australia you do have to vote – or face a $20 fine - but you don’t have to cast a vote that counts.

Reuben Elias from Redcliffe near Brisbane said he ‘voted’ early, but had simply posted an empty ballot paper as he didn’t know which way to lean.

“I put in a blank, so it's invalid. It‘s too undecided what the Yes are saying and the No are saying, so this way I can’t be accused of being a racist,” he said.

I asked if he really thinks that being a ‘No’ vote would mean he was seen that way?

“Probably. I think so. There's a lot of conflict. I believe this is dividing the country, not bringing it together. So that's why I voted the invalid," he told me.