Federal Labor leader Bill Shorten wants the longer term implications of a proposed new constitutional indigenous advisory body to be worked out before a referendum is held.
Federal MPs are split over the Uluru Statement released in central Australia last week calling for an indigenous body to be enshrined in the constitution, a Makarrata or treaty commission and a truth and reconciliation process.
Mr Shorten told the Labor caucus in Canberra on Tuesday any constitutional change required "an understanding of what the post-constitutional change settlement is".
This meant sorting out additional issues that are not of themselves part of the actual changes to the wording of the constitution.
Labor senator and indigenous leader Pat Dodson told caucus it was important to wait for the final recommendation of the Referendum Council, set up to advise the prime minister and opposition leader on the way forward.
Senator Dodson said it was also vital to have "the prime minister at the front" if change was to occur.
The Uluru document dumps a planned referendum for the recognition of indigenous as first peoples in the constitution, which some Aboriginal groups have branded tokenistic.
Instead, it calls for the enshrining in the constitution of an advisory body to give indigenous people a say on laws and policies that impact them.
In his initial response, Prime Minister Malcolm Turnbull said only "conservative" constitutional changes would succeed at a referendum.
His deputy Barnaby Joyce said the body proposal as an overreach.
Cabinet minister Matt Canavan is sceptical.
"I am a little sceptical though of the need for another body for indigenous peoples when the main game here for me is unlocking the economic opportunities that exist for indigenous peoples," he told reporters in Canberra on Tuesday.
Nationals MP George Christensen said the idea of a separately constituted body was "dangerous to democracy".
However, Liberal MP Julian Leeser said it was a "big breakthrough" and Indigenous Affairs Minister Nigel Scullion has urged everyone to be "courageous" and listen.
Senator crossbencher David Leyonhjelm opposes the idea of a constitutionally recognised body.
"I'm fundamentally opposed to anything that distinguishes between Australians on the basis of race," he said.
Professor Megan Davis, a member of the Referendum Council, argues the Uluru proposal offers "quite modest" changes.