A prominent leader of the campaign against an Indigenous voice will take the national stage to attempt to sway voters as the referendum enters its final stretch.

Warren Mundine is set to address the National Press Club on Tuesday.

New polling showing support has dropped dramatically for constitutionally enshrining an advisory body and that the ‘no’ side maintains a majority of voters, has bolstered Mr Mundine’s message ahead of his speech.

Mr Mundine has argued the voice is divisive and will not adequately represent regional and remote Aboriginal and Torres Strait Islander people.

He has however also separated from the attack lines of fellow Indigenous ‘no’ campaigner Senator Jacinta Nampijinpa Price, arguing voting against an Indigenous advisory body in the constitution would help progress treaties, something he supports.

Opposition Leader Peter Dutton has shut down any talk of a treaty.

But ‘yes’ campaigners remain optimistic they can secure the support of a majority of Australians in a majority of states and have the referendum succeed.

Prime Minister Anthony Albanese said misinformation about the voice had been knowingly shared by its opponents ahead of the referendum.

“What has occurred during this campaign is a lot of information being put out there, including by some who know that it is not true. They know the voice won’t be sitting down with the Reserve Bank determining interest rates,” he told reporters in Adelaide.

“We know there’s a lot of (misinformation) and that’s before you get to some of the quite unsavoury comments that are being made or claims that are being made.”

The prime minister said the voice was a “generous request” and he was confident of an overwhelming number of Indigenous Australians supporting the proposal.

“It’s very clear what is being forward and that is why so many groups … have looked at this and said this is the right thing to do which is why they’re advocating a ‘yes’ vote,” Mr Albanese said.

He said he would respect the outcome of the referendum, despite polls showing the ‘yes’ vote had dropped to 36 per cent, according to Newspoll.

South Australia – a crucial swing state – has a proud tradition of leadership when it comes to “substantial social reforms”, Premier Peter Malinauskas said.

“It is my hope we can do the same again in respect to the voice,” he said.

“We know it’s not necessarily going to be easy but it’s something we are wholeheartedly committed to at a state level, having already legislated a voice to the state parliament.” 

Australians are being asked whether they want to recognise Indigenous people in the constitution by enshrining an advisory body known as the voice that will be able to make representations to government and parliament but not hold any veto powers.

The referendum will take place on October 14.

By Dominic Giannini and Andrew Brown in Canberra