A national gathering of young justice advocates has unanimously backed calls to raise the age of criminal responsibility to 14 years old nationwide.

The Indigenous Youth Justice Conference, hosted on October 30, heard evidence from a range of experts about the need for change in the justice system.

Australia's first Indigenous senior counsel Tony McAvoy said there was no need to delay the change.

"These laws harm children at a critical time in their development, while doing nothing to address crime," he said.

"In fact, locking up children locks in a pattern of reoffending which is detrimental to individuals and the broader community.

"When we put children into the criminal justice system including prison, they suffer lifelong harm that cannot be undone."

Mr McAvoy said there was an overwhelming majority of people who wanted to see the age of criminal responsibility raised.

A Federal Attorney General spokesperson said Minister Mark Dreyfus had met with state counterparts to form a working group on the issue.

"This working group will pay particular attention to addressing the overrepresentation of Aboriginal and Torres Strait Islander children in the criminal justice system," he said.

"The decision by the Northern Territory to raise the age to 12 is evidence of the progress being made as a result of the co-operative approach to this issue.

"The Attorney-General and the Minister for Indigenous Australians are working together closely on the justice outcomes within the National Agreement on Closing the Gap."

Among that agreement is a target to reduce overrepresentation of Indigenous children in the justice system by 30 per cent by 2031.