Negotiating a treaty between the state of South Australia and local Indigenous people is "unfinished business" originally instructed by British king William IV, an academic says.

Daryle Rigney, the head of Indigenous strategy and engagement at Flinders University, said directions from the king (who reigned from 1830 to 1837, preceding Queen Victoria) about how SA should be established included "clear instructions there should be treaties and bargains entered into".

"And they weren't," he told ABC Radio Adelaide's Mornings program.

Mr Rigney, a citizen of Ngarrindjeri nation, said a treaty would realign the relationship between Aboriginal people and the State Government and address "real questions about justice".

"It's unfinished business for the Ngarrindjeri nation and for other South Australian communities."

Premier Steven Marshall last month scrapped preliminary moves by the former ALP government to negotiate a statewide treaty.

This was despite Labor signing an agreement with the Yorke Peninsula's Narungga people as the state's first step towards establishing a treaty.

Mr Marshall has instead pledged to work with the community to "deliver practical outcomes in key areas, such as economic participation, justice, health and education".

He yesterday announced the appointment of former treaty commissioner Roger Thomas as the Government's new Commissioner for Aboriginal Engagement.

"I believe that right across government, we have to find more practical and timely ways to support our Aboriginal communities," Mr Marshall said.

"I have asked all my ministers to discuss with their agencies actions that can be taken to make a difference for Aboriginal people.

"Communities also want governance processes within their own communities to ensure that when they are engaging with the Government, the representation of their people's views is effective."

Treaty discussed but blocked in 1840

The 1836 Letters Patent establishing South Australia states in part:

"Provided always that nothing in those letters our Letters Patent contained shall affect or be construed to affect the rights of any Aboriginal natives of the said province to the actual occupation or enjoyment in their own persons or in the person of their descendants or any lands therein now actually occupied or enjoyed by such natives."

William IV issued Letters Patent to establish the province of South Australia. ( Website: State Government, via State Records of SA, GRG2/6 )

Dr Robert Foster, the head of history at the University of Adelaide, said the Letters Patent recognised that Aboriginal people could have prior ownership of the land but did not in itself constitute anything by way of a treaty.

"In the setting up of the colony, there were negotiations between the colonisation commissioners and the colonial office, and there was some discussion about how Aboriginal people should be negotiated with for land; whether or not certain land should be set aside and those sorts of things.

"It didn't get resolved until 1840, when governor George Gawler said they couldn't enter into bargains or treaties with the Aboriginals but they would hold land in trust for them.

"The idea of a trust holding land in the form of reserves and so forth became policy for other colonies across the country."

A dedication to 'serve'

Mr Rigney has sat on a number of boards during his career, including the Ngarrindjeri Regional Authority and Ngarrindjeri Enterprises, the United League of Indigenous Nations, and as director for the Australian Centre for Social Innovation.

He was also awarded Person of the Year in the 2013 NAIDOC awards and, among other leadership roles, has participated in a number of Ngarrindjeri and state government leaders' forums.

Mr Rigney said he was also a physical education teacher, once upon a time, "although you might not believe it in the body that you see today".

"I've been fortunate enough to meet some outstanding people in my work and my time, who've kind of inspired me to take up the challenge of trying to think about justice and social justice and how you make that work," he said.

"I see myself as somebody who wants to make a contribution as best I can."

He said he'd been actively involved in nation-building work, "which builds on 30 years of research from Harvard University".

"A treaty is about establishing a relationship, a new relationship with the state.

"I think there needs to be treaties at different levels, because different governments have different powers."