Indigenous leaders have backed away from the idea of asking people to vote for a voice to parliament before any details were worked out, as they come to grips with the reality of a Morrison government.

Speaking after a "milestone" speech by former High Court chief Justice Murray Gleeson in Sydney on Thursday night, Noel Pearson conceded Mr Gleeson was right about a proposed referendum when he said: "Australians, and parliament itself, would want to see what the body looks like, and hear what the voice sounds like, before they vote on it."