The Greens want a treaty with First Nations Australians as a condition of backing a referendum on a Voice to Parliament.
Australia's third-largest party has outlined its negotiating stance on the proposed referendum, which could prove vital if the Coalition opposes the proposal.
Labor made a Voice to Parliament central to its election bid, pledging to hold a vote in this term of government, which will run until May 2025 at the latest.
The Greens on Tuesday revealed they had given "full backing" to Indigenous affairs spokeswoman Lidia Thorpe, a Gunnai Gunditjmara and Djab Wurrung woman, to negotiate with the government on how the referendum would function.
Senator Thorpe pledged to deal "in good faith" with Indigenous Affairs Minister Linda Burney, signalling a Treaty and truth-telling commission - two long-standing Greens aims - would be "on the table".
"If the Prime Minister [Anthony Albanese] wants to heal this nation and unify people, he needs to understand that sovereignty never ceded is more than a slogan. It's a call to action. It's time to tell the truth about our country," she said.
"The PM said that Treaty is 'ambitious'. After 230 years of colonisation, we need ambition. I challenge the PM to do the work.
"Any process that could be rushed through the Parliament in six months is unlikely to involve any meaningful transfer of power. Self-determination is a human right."
The Greens will also demand Labor pass the United Nations Declaration on the Rights of Indigenous Peoples Bill 2022, and implement the remaining recommendations from the Royal Commission into Aboriginal Deaths in Custody and the Bringing them Home Report.
Any referendum would need approval from Parliament, making the Greens' 12 Senate votes pivotal if the Coalition opposed the proposal.
Coalition leader Peter Dutton is yet to reveal the party's stance.
IN OTHER NEWS:
Labor has pushed for a simple Yes-No referendum question, with details on how the Voice would function to be thrashed out after.
It has suggested Australians vote on whether they "support an alteration to the Constitution that establishes an Aboriginal and Torres Strait Islander Voice".
The Greens said every First Nations group in Australia should have input into a Treaty process, which they hoped would have strong cross-party backing.
That would require a fully-funded independent body "empowered to undertake all processes required" to strike a treaty underpinned by the United Nations Declaration on the Rights of Indigenous Peoples, the Greens said.
Its model for a truth-telling commission would include the power to hold hearings, while working to ensure truth telling and justice were "recognised as an essential healing process for the whole of the country".