The federal opposition is yet to reach a position on the Indigenous voice to parliament, following the unveiling of the question to be put to a referendum.
Opposition Leader Peter Dutton has called for the government to release the solicitor-general's advice on the voice.
Mr Dutton said the full legal implications of the voice to parliament and how it would operate needed to be released.
"It's absolutely essential that the prime minister releases the solicitor-general's advice. From what I've read in media reports, the solicitor-general has concerns about these very words," he told reporters in Canberra on Thursday.
"In the absence of that advice, and in the absence of detail from the prime minister, how can the Australian public make an informed judgment about a very, very important issue?"
Prime Minister Anthony Albanese and members of the referendum working group on Thursday outlined the question to be put to the public at the referendum, along with the design principles and details of its function.
Voters will be asked: "A proposed law to alter the constitution to recognise the First Peoples of Australia by establishing an Aboriginal and Torres Strait Islander voice. Do you approve this proposed alteration?"
Mr Dutton said releasing the design principles was not enough.
Nationals leader David Littleproud also called for the legal advice to be released, saying his party remained opposed to the voice on the basis it would add another level of bureaucracy.
There was no malice in the party's position as it also wanted to see Indigenous wellbeing improved, he added.
But changing the constitution would allow legal challenges to arise.
"We have the framework, we just need the bureaucracy to work better," Mr Littleproud said, pointing to local Indigenous bodies across the country.
"Programs in Cunnamulla will probably not work in Wilcannia or in Carnarvon. You have to have the agility to have bespoke solutions for these communities because they are different in their challenges and their opportunities."
Former deputy prime minister Barnaby Joyce told parliament the government was trying to "guilt" people into supporting the voice.
"It's not racist to vote no," he said.
Conservative think tank the Institute of Public Affairs has come out against the proposal, calling it a dangerous demand.
Institute executive director Daniel Wild said the voice would not lead to tangible outcomes.
"The overwhelming majority of Australians agree that more work needs to be done to achieve better outcomes for Indigenous Australians in the outback," he said.
"However, this proposed Canberra-based, race-based body for activists will achieve nothing towards this."
