Party leader Adam Bandt and Indigenous spokeswoman Lidia Thorpe will begin negotiations with Labor on the referendum to enshrine the voice in the constitution, following a party room meeting.

As Acting Prime Minister Richard Marles reiterated the government's pledge to establish the voice during the current parliamentary term, Senator Thorpe said it was critical for all elements of the Uluru Statement to be implemented.

"If the PM 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 on Tuesday.

"We will be putting treaty and a truth commission on the table."

The Greens spokeswoman also called for the government to implement all recommendations from the 1987 royal commission into Aboriginal deaths in custody, as well as the 1997 Bringing Them Home report.

"The PM said that treaty is 'ambitious'. After 230 years of colonisation, we need ambition. I challenge the PM to do the work," Senator Thorpe said.

"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 said they were ready to negotiate with the government in good faith on the voice to parliament, as well as work across party lines.

Mr Marles said the government would prioritise the voice over a treaty or truth telling commission, but was committed to taking a voice in the constitution to a referendum.

"We're focusing on the voice. That was the commitment that the prime minister made ... and that is the path that we're walking down," he told ABC radio.

"It's really important that we walk down a path where we are able to achieve success here."

Mr Marles said the government would need to publicly campaign to win over voters who weren't sure what the voice was.

"We also do believe that the sentiment is there to make this change," he said.

"We really feel that in having the proper campaign out there ... this can be a really uplifting moment for the nation, a moment where we really do take a step forward in the growth of our nation."

Prime Minister Anthony Albanese revealed at the Garma Festival in the Northern Territory the draft question that could be put to voters.

The proposed question is: "Do you support an alteration to the constitution that establishes an Aboriginal and Torres Strait Islander Voice?".

While an exact time frame for the referendum hasn't been confirmed, it's expected it will take place in 2023.

Australian Associated Press