Conservative critics are particularly alarmed that the body would be able to consult directly with executive government,which refers to ministers and the public service,as well as making representations to parliament. Craven,among others,has argued this gives it too much scope to interfere in daily government while also leaving open the possibility of High Court challenges.

McCormack,who last year suggested the Nationals could revise their opposition to the Voice once more detail was released,said Albanese’s final referendum wording had not satisfied his concerns.

The Voice would “cause another level of bureaucracy and that worries many of the people I’ve spoken to”,he said,adding that “rather than actually providing a clearer path,it has made people more concerned”.

“My position has not changed. I’m worried about this,I don’t think it will enhance the lives or livelihoods of those who need it most,” he said. “There is a lot hanging on this for the prime minister – he has put all his chips behind it.”

Entsch,the Queensland Coalition MP who championed same-sex marriage within his party,said Thursday’s release of further detail – which the government hoped would assuage some critics – had not done enough to explain how the Voice would work.

He said prominent Indigenous leaders in his electorate did not support the Voice and were sceptical about its ability to reverse disadvantage.

“Things have got to improve[for Indigenous Australians],” he said. “But they’re on an all-or-nothing campaign. My fear is that we lose it all,” he said.

“They’re going to do it on a vibe,on a slogan,but what does that slogan actually mean?”

Moderate Liberal Bridget Archer,one of only a few Coalition MPs who have publicly backed the Voice,repeated her call for Liberals to be able to campaign for whichever side of the referendum they believed in. Entsch also supports a free vote.

“The party room hasn’t decided a final position on the Voice and I remain hopeful that at least there will be a free vote,” Archer said.

Her call was backed by former prime minister Malcolm Turnbull,who said Coalition MPs should have a conscience vote.

“Given the strong differences of opinion in the party room,I would expect Dutton to allow a free vote as[John] Howard did over the republic or as I did over same-sex marriage. This would allow prominent Liberals to campaign on either side of the debate,” he said.

Kennett,a member of the Voiceco-design process led by Indigenous leaders Marcia Langton and Tom Calma,said Albanese was making a fatal mistake by enshrining the Voice in the Constitution. Kennett argued just recognition of Indigenous Australians should be added to the Constitution because taking a more minimalist approach would provide a better chance of winning.

“I don’t understand why the prime minister doesn’t recognise,regardless of what the polls say,that he is putting at risk the referendum failing – which I don’t want to happen,” Kennett said.

Cut through the noise of federal politics with news,views and expert analysis from Jacqueline Maley.Subscribers can sign up to our weekly Inside Politics newsletter here.