The Australian Greens say the release of an Amnesty International report into Indigenous incarceration should restart a national conversation about Justice Reinvestment as an alternative to "lock 'em up" prison culture.

Australian Greens spokesperson for legal affairs Senator Penny Wright, who chaired a 2013 inquiry into Justice Reinvestment, said some of the momentum for Federal action had been lost after the election of the Abbott Government.

Prime Minister Tony Abbott must urgently clarify if he intends to reverse his party's election promise to make multi-million dollar cuts to indigenous legal aid, say the Australian Greens.

The Attorney General's Department last night confirmed frontline services could not be isolated from the $42 million cut to indigenous legal aid funding under questioning from Senator Rachel Siewert and Senator Penny Wright.

The Australian Greens have condemned Tony Abbott's cuts to the Indigenous Legal Assistance and Policy Reform Program, saying it goes against all his past rhetoric and will exacerbate the shameful incarceration rates for Indigenous Australians.

"Tony Abbott says he wants to prioritise efforts to end Aboriginal and Torres Strait Islander disadvantage, but cutting Indigenous legal aid funding undermines this commitment," Senator Rachel Siewert, Australian Greens spokesperson on Aboriginal and Torres Strait Islander issues.

The Australian Greens have backed calls to divert non-violent Aboriginal and Torres Strait Islander offenders with substance use problems into rehabilitation or treatment programs in place of prison terms.

 "We need Federal leadership for a new approach across the country to fix what is clearly a very broken system," said Australian Greens spokesperson on legal affairs, Senator Penny Wright.

"We must address the underlying causes of disadvantage, which mean many Aboriginal people do not have the same opportunities and support as other Australians.

Increasing over-representation of Indigenous youth in juvenile detention shows the drastic need for a new approach to justice in Australia, say Australian Greens Senators Penny Wright and Rachel Siewert.

New figures from the Australian Institute of Health and Welfare show Indigenous young people account for 53 per cent of all youth in detention and were 31 times as likely as non-Indigenous young people to be in detention, up from 27 times as likely in 2008.