Ngunnawal Elder Aunty Violet Sheridan has called on Australians to "stand with us" on an Indigenous Voice to Parliament at a "yes" campaign event in Canberra on Sunday.
Around 600 people rallied at Haig Park to support the proposal, according to Yes23 campaign organisers.
The Come Together for Yes event was one of more than two dozen held across the country, as campaigners look to shift the debate from Parliament and into the community.
Speaking at the Canberra event, Ms Sheridan the Voice would empower communities.
"Our children will have a better future because we will have a say, we will have a say because we'll have a right to vote our community and people in there to sit at the table, to advise the government where they're going wrong," she said.
"We need the non-Indigenous people like yourselves, but also the multicultural people, to stand with us to make a difference when the referendum vote comes."
Katrina Fanning, a Wiradjuri woman and 2023 ACT Australian of the Year, said has spent more than 20 years in the public service and believes the Voice will "help them to be able to do their jobs better".
"I've worked with so many people who just need better information, better guidance on the things that they're trying to deliver," she said.
It comes as polling shows a decline in support for the Voice, with recent surveys from both Newspoll and Resolve indicating fewer people were now in favour of the proposal.
Yes23 campaign director Dean Parkin said there were a number of polls and "they tell differing stories of the levels of support".
Mr Parkin said campaigners were "confident that we've got the right approach to really engaging people on the ground".
He said many Australians still haven't heard about the Voice but they hoped to use organisations and volunteers supporting the campaign to "extend the conversation" in the lead up to the referendum.
"When you have the conversation in community there's a lot of curiosity. There's a lot of goodwill. We've just got to make sure that we get that out to as many people as we possibly can over the next few months," he said.
ACT campaign director Freya Brent said, as part of this weekend's event, the campaign has been recruiting volunteers to knock on doors, run stalls and distribute flyers in an effort to reach every voter across the ACT over the coming months.
She said volunteers will also be trained up to take part in phone banking sessions to get the message out to voters across Australia.
"[It's a] very traditional campaign, but it's a very big grassroots campaign with a lot of people involved," she said.
"We've got everything to win and nothing to lose with this vote."
She said hundreds of people have already signed up to volunteer in the ACT, with that number expected to grow to up to 2000.
Among those signing up to volunteer on Sunday was Liz Lester, who said she will be assisting with mail drops and phone calls, among other activities.
"In Australia, it's actually time we faced some truths and made some changes," she said.
Ms Lester said she lived in Murrumbateman and would be trying to get information about the Voice out to communities in Canberra and New South Wales.
The constitutional alteration bill passed the Senate last month but the government has yet to announce a referendum date.
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