For Aboriginal community leader Karen Gibson, Australia’s historic referendum on Saturday is an opportunity like no other.

“I never thought I would experience it in my time here,” says the proud Yalanji and Nyungkul woman. “My ancestors were invisible. They’re still invisible. I want to be visible.”

This weekend Australians will vote Yes or No to recognising First Nations people in the constitution by establishing a Voice to Parliament – a body that would advise the government on issues that affect Aboriginal and Torres Strait Islander communities.

The referendum was proposed as a way to try and unite the country – but it’s been a difficult, and often acrid, campaign. The polls now point to a win for No on Saturday.

Some of those divisions are on display in Queensland, where Karen lives. It has one of the highest Indigenous populations in Australia, but from the start of the campaign it’s been labelled as an unwinnable state. It tends to trend conservative on social issues – and opinion polls have long shown support for Yes well below 50% among its residents.

Karen’s community of about 800 people – in the far north of Queensland – is surrounded by lush rainforest and bordered by the Mossman River, a popular tourist attraction. While she sees the referendum as a chance for change, she’s still bracing herself for a No.

“Even though I want Yes to win, I still have this almost high expectation that might prove my point about what Australians are made of,” Karen says. “If No wins then I would say ‘I told you so’, because of the expectation that I’ve been born with – that nothing will work for us.”

Aboriginal and Torres Strait Islanders make up nearly 4% of Australia’s population of more than 25 million. So although polls show most First Nations Australians support a Yes vote, the reality is that the people who will actually decide this referendum – and the fate of Indigenous communities – are the majority non-Indigenous.

Fellow Queenslander Noel Pearson – one of the architects of this referendum – says this vote is crucial for righting historical wrongs.

“What we’re trying to sort out here is a British legacy – the bloody, miserable legacy of colonisation,” the Guugu Yimidhirr man says. “Our Aboriginal and Torres Strait Islander people have been pushed to the margins, living an average life expectancy in the remote communities of not much more than 50. We are trying to fix the aftermath of two centuries of colonial legacy.”

Australia is no doubt going through a historical reckoning – this is a country so often touted as a multicultural success story. But its first inhabitants face gaping disparities in employment, infant mortality, and rates of suicide and incarceration.

“[The Voice] will recognise the truth of this country and that will bring us together as a nation,” Australia’s Indigenous Minister Linda Burney said last weekend at a music festival in the Aboriginal town of Yarrabah, just south of Cairns.

“If you think No is the answer, I will say that No means no change – it means the status quo. And if there’s one thing that’s got to change in this country, that’s better-quality outcomes for our people.”

Suzanne Andrews, the chief executive of Gurriny Yealamucka health services in Yarrabah, knows all too well the poor health outcomes in communities like hers. One of their priorities at the moment is rheumatic heart disease. It was virtually eradicated in wider Australia in the 1970s but it has returned here and in other places with concentrated Indigenous populations.

“When we are making decisions around health, we need to be making those decisions from us people on the ground here in communities, not in Canberra,” she says.

“When you look at Aboriginal communities and the conditions they are in – there’s a housing issue. When you have overcrowding in the houses, you have multiple health conditions in that house. How do we start to tackle all of that? It’s not just about fixing the house, it’s fixing the individual and fixing the family and then the wider community.”

But it’s been a bitter debate – and one that has been full of mis-and-disinformation. Some conservative voters feel the proposal is divisive, which is a central theme of the No campaign’s messaging.

“If you want to have a good functioning country, you can’t have divisions, you can’t have separations,” says Cairns resident Frank Titan who will vote No on Saturday.

“I think that is very wrong and unfair and really sad. We’re not racist people here, we’re fair dinkum Australians. Everyone is equal.”

The referendum has also exposed divisions within Indigenous communities. Many feel like they are reliving past trauma and discrimination, and some are critical of the way the referendum has been pursued.

Lidia Thorpe, the first Aboriginal senator for the state of Victoria, left the Greens earlier this year over the party’s support for the Yes vote. Ms Thorpe, and the grassroots Indigenous movement she’s come to represent, argue that the negotiations for legally-binding treaties with Indigenous peoples should have been prioritised ahead of the Voice. Australia is the only former British colony without such a treaty.

“The Voice is about assimilating us into the colonial constitution to make us nice, neat little Indigenous Australians that will continue to be oppressed by the coloniser,” she says.

“The amount of money that is going on this referendum while our people are hungry and homeless and suicide rates are through the roof – I think [it] just shows you how wrong this country is in how they think they can fix the ‘Aboriginal problem’.”

This is a vote that has been decades in the making – calls for both constitutional recognition and greater Indigenous political representation have long dominated First Nations activism.

And win or lose, the outcome will likely define Australia’s relationship with its first inhabitants for decades to come.

Additional reporting by Simon Atkinson.