Crossbench MPs have been briefed on a proposed Indigenous voice to parliament as debate roars about what detail should be unveiled before a referendum.

Independent MP Allegra Spender backed the Labor government’s approach after correspondence with them on Thursday, saying they’d outlined the parliament of the day would shape what form the voice takes.

She said the briefing had made clear the voice would have some “particular qualities” including not sitting as a third chamber of government, adding a referendum was about tweaking the constitution rather than voting for a law change.

“The constitution is about principles, and this is a question of changes to the constitution, this is not a question of changes to legislation,” she told ABC Radio.

“I support the government in where it is going and I support that the parliament of the day will determine what that looks like.”

Ms Spender said there was strong crossbench interest in the voice regarding how Indigenous communities could help shape it.

“This is something that will be there to … give Aboriginal and Torres Strait Islander people a voice on the services that affected them,” she said.

“That is the fundamental reason why I’m supporting this, because we’ve spent decades with policies and laws that are in effect for Aboriginal and Torres Strait Islander people but they do not have the voice in terms of making sure this is actually what the communities want.”

Opposition leader Peter Dutton continued to call for more detail before his party would take a position, despite his coalition partner Nationals already having seen enough to declare they couldn’t support it.

“They’ve had a really good conversation in their party room, there’s obviously a clear majority view they don’t think the government has provided enough detail,” he told Nine.

“Pat Dodson from the government is coming out saying there will be no detail and I don’t know how you can say to the Australian public, we want you to consider a really important aspect of public policy … and you end up in a situation where the government won’t provide any detail ahead of a vote and people reasonably are asking why.”

Labor minister Amanda Rishworth said Mr Dutton was being “disingenuous” to create “doubt and uncertainty” and called on him to show leadership.

“What we are putting forward is a very simple proposition in terms of constitutional change – do First Nations people deserve to have a voice in the issues that affect them?” she told ABC Radio.

“His party is clearly divided on this, but he needs to be a leader when it comes to this and listen to the voices of Aboriginal and Torres Strait Islander people.”

– AAP