Young Australians are expected to be key to the Indigenous voice referendum succeeding.
Cabinet minister Don Farrell told the National Press Club voters aged over 55 tended to oppose the voice, while Australians under 35 overwhelmingly backed it.
"That young cohort will be enough to counter the 'no' vote and I think it will be the young people who will deliver Indigenous voice for Australia," he said on Thursday.
"If it (referendum) was held this Saturday, I think it would get up.
"The majority of Australians voting for it and there would be a majority of states."
Senator Farrell said he was still "optimistic" about the referendum on the voice to parliament.
"We've tried the republic, it didn't work, so I think the voice is the correct one," he said.
"There's no other people in our community who suffered such disadvantage as Indigenous Australians, and it's time that we had recognition in our constitution for them."
Meanwhile, the Royal Australian and New Zealand College of Psychiatrists and the Australian Indigenous Doctors Association have backed the proposed constitutional change.
The Indigenous voice would lead to a significant step forward and would also result in better mental health outcomes, the college said in a statement.
"We are acutely aware of the trauma inflicted on Aboriginal and Torres Strait Islander peoples due to the ongoing impact of colonisation, dispossession, and systemic racism and inequality," it added.
Australian Indigenous Doctors Association chief executive Donna Burns said the voice would improve the wellbeing of Indigenous people.
“The data overwhelmingly demonstrates that an unacceptable health gap persists due to the health inequities experienced by Aboriginal and Torres Strait Islander peoples," she said.
“The position that AIDA holds is based on our vision to rectify the continued health disparity that disproportionately affects Aboriginal and Torres Strait Islanders."
Laws to set up the Indigenous voice referendum passed the House of Representatives on Wednesday.
The bill, which will finalise the referendum question and constitutional changes put to the public, will now go to the Senate.
It's expected to pass federal parliament later this month, with the referendum to be held between October and December.
Indigenous Australians Minister Linda Burney urged people who did not know much about the voice to consider the inequality people faced before making up their minds.
"I would say to those people ... look into your heart and look into the situation Aboriginal people are in in this country," she said.
