Campaigners for the Indigenous voice say the referendum will be won through "honest conversation" at train stations, shopping malls and family homes, not social media.
Prime Minister Anthony Albanese announced on Wednesday the vote on whether to change the constitution to recognise Aboriginal and Torres Strait Islander people through an advisory body would be held on October 14.
Mr Albanese campaigned on Thursday in Tasmania, considered a must-win state for the 'yes' camp.
Prominent Indigenous lawyer and 'yes' campaigner Noel Pearson was optimistic of a win, despite signs the 'no' case is dominant in Queensland and Western Australia.
"We have everything in front of us, we have a world to gain," Mr Pearson told ABC radio.
He said the growing base of volunteers would be instrumental to the 'yes' campaign.
"We're not going to win this on social media, we're gonna win it at the train stations, in the malls, at the houses of people that we knock the doors on," he said.
"My belief is that this is to be won through honest conversation between Australians."
Mr Albanese was joined in Hobart by Tasmanian Liberal premier Jeremy Rockliff, federal Liberal MP Bridget Archer and independent MP Andrew Wilkie, all of whom support the 'yes' case.
"It should be a moment of national unity and I'm pleased that every premier and chief minister is supporting a 'yes' vote," Mr Albanese said.
"This isn't something that's come from the Labor Party or the Liberal Party, this is something that has come from Aboriginal and Torres Strait Islander people themselves."
The Australian Electoral Commission has so far identified 10 threads of disinformation circulating on social media, ranging from the constitution being invalid to the referendum being "rigged".
Campaigning in Queensland, Indigenous Australians Minister Linda Burney was confident the state would back the constitutional change.
"I have enormous faith in this state. This state is going to be loud and clear about justice and about doing the right thing, I have got no doubt about that," she said.
Success will require a majority of voters and a majority of states voting in favour.
If the referendum succeeds, the federal parliament will legislate the details of the voice's composition, functions, powers and procedures.
Opposition Leader Peter Dutton said the $450 million cost of the referendum could be better spent helping families or small businesses.
"I cannot find a time when a prime minister has proposed a bigger change to the constitution without being able to explain what it is about," he told 2GB radio.
Mr Dutton said if the government had offered a simple question of recognising Indigenous people in the constitution "the public in 2023 would support it overwhelmingly".
ACTU president Michele O'Neil said thousands of union members backed the 'yes' campaign.
"Union members want to make sure that we have a fairer country. They want to make sure that Aboriginal and Torres Strait Islander people's voices are heard and that we recognise their continuous connection," she said.
"There's many thousands of ordinary union members who are stepping up every day to support the 'yes' campaign."
Early voting for the referendum begins on October 2, but because of a public holiday observed in the ACT, SA, NSW and Qld, those jurisdictions will open pre-polling on October 3.
