Leading campaigners for and against an Indigenous voice to parliament will front a hearing as one of the scheme's proponents warns of the difficulty in putting forward a winnable proposal.
Australia's second law officer has backed the government's wording for the Indigenous voice, advising it isn't just compatible but "enhances the system".
The High Court will be left in no doubt that parliament retains its supremacy if the Indigenous voice referendum is carried, a key figure in its design says.
The federal Referendum Working Group has met in Adelaide - but hasn't released the wording of a question about a proposal for an Indigenous voice to parliament, as expected.
The federal government won't push through legislation to establish an Indigenous voice to parliament if a referendum fails but the prime minister is instead focusing on ensuring its success.
Russia has launched referendums in four occupied areas of Ukraine expected to be used by Moscow to justify annexation, but Kyiv says the voting is mandatory with residents threatened with punishment if they don't take part.
Three "ingredients" key to a First Nations voice to parliament successfully passing a referendum will be the focus of a working group of First Nations leaders.
