Twenty years after a royal commission scrutinised the high rate of Aboriginal deaths in custody, the over-representation of young indigenous Australians in the criminal justice system is even worse than back then - a situation branded "a national disgrace" by a parliamentary committee.

Despite the commission making 300 recommendations aimed at keeping young Aboriginal people out of jail, they are now 28 times more likely to be locked up than their white counterparts, according to a report by the lower house committee on Aboriginal and Torres Strait Islander Affairs.

The report found that federal, state and territory governments had all failed to address the problem adequately.

"This is a national tragedy, and questions must be raised as to why the situation has worsened so dramatically after the sweeping reforms recommended by the royal commission," it said.

The same depressing litany of factors - alcohol and substance abuse, limited education, unemployment, inadequate housing, entrenched poverty and poor relations with police - was cited to explain the disproportionate number of indigenous juveniles and young adults in Australian jails.

While Aborigines make up only 2.5 per cent of the Australian population, they represent one-quarter of people behind bars. The figures are even worse in the younger age bracket: 59 per cent of inmates in juvenile detention centres are indigenous.

In the past decade alone, the incarceration rate for Aboriginal people has soared by 66 per cent.

The committee described the over-representation of indigenous youth as a "national crisis", and called for wide-ranging government action to tackle it.

It made 40 recommendations aimed at keeping young Aborigines out of the criminal justice system, including consideration of sentencing options other than prison and a cultural awareness programme for police.

Mick Gooda, the Aboriginal and Torres Strait Islander Social Justice Commissioner, called on the Government to implement the recommendations with urgency.

"We must act now before we lose another generation to the criminal justice system," he said.