Malcolm Turnbull’s criticism of the Referendum Council’s report on indigenous constitutional recognition — that it contained too little detail — will be answered today with a sweeping set of proposals to be unveiled by former High Court judge Michael Kirby.

The legislative detail for what the Prime Minister dismissed last year as a “very big new idea” — an indigenous advisory body enshrined in the Constitution — has been built up by lawyers working with a group co-founded by constitutional expert and Liberal MP Julian Leeser.

Mr Leeser, who co-chairs with West Australian Labor senator Patrick Dodson a committee examining the Referendum Council’s recommendation and previous proposals, stepped away from the Uphold and Recognise organisation after being elected but has been an enthusiastic supporter of a “voice” to parliament.

The group (no connection to Canberra’s defunct Recognise awareness-raising campaign) is backed by corporate and institutional players including the Australian Catholic University, the University of NSW, law firms Allens and Linklaters, and Westpac and Commonwealth banks.

Lawyer Damien Freeman, who founded the group with Mr Leeser in 2015, said the policy detail to be launched at NSW Parliament House today responded to Mr Turnbull’s concerns.

“The first challenge was getting indigenous consensus about what the big idea was, which came with the Uluru Statement,” Mr Freeman said. “The second challenge was to work out what the detail of those big ideas looks like — and we’re now showing what that is, with a range of options.”

The task now was to find an option acceptable to all.

The plans include two proposals for how the voice to parliament could work. The first is a “speaking for country” option where the Constitution is amended to recognise local entities and a law passed detailing how these groups would affiliate to create a conduit between local groups and parliament. The second option is an advisory council enshrined in the Constitution and a law passed to stipulate its roles, functions and composition and provide for local indigenous organisations to send delegates to a national conference where members are selected.

There are also three extra-constitutional suggestions for a makarrata, or agreement and truth-telling process, including creating a royal commission for makarrata and options for creating a formal declaration of recognition outside the Constitution.

Mr Kirby said he had sympathy for Mr Turnbull’s concerns because he initially had shared them. He called on Mr Turnbull to reassess because “thoughtful people, with a sense of justice, will sometimes reconsider their intuitive reactions (and) this is such an occasion”.

“The key to real progress goes beyond harmless symbolic acts, like acknowledging on public occasions the traditional custodians of the land, or by inserting a poetic recital in our constitution so long as it has no legal consequences,” he said.

“The key … lies in listening to the voices of our First Peoples whenever important issues arise, especially affecting them and their communities.”

The drafting work has been guided by indigenous lawyers Megan Davis and Noel Pearson, as well as chairman Sean Gordon.

ACU vice-chancellor Greg Craven, a constitutional lawyer who supports the change, said denying the recommendation “merely to be heard (in the parliament), strikes me as suggesting something impervious in the Australian soul”.

READ: The Australian