ALMOST two in five young Australians in the juvenile justice system are Indigenous.
And they are entering the system younger, and staying longer.
The gross over-representation is detailed in the latest Australian Institute of Health and Welfare report, which shows there were 2,820 Inidgenous young people under juvenile justice supervision on an average day in 2010-2011.
The report says even though only 5 % of young Australians are Indigenous, they comprise 39 % of those under supervision.
They are also entering the system younger than non-Indigenous young people, and staying longer.
The institute's spokesperson Tim Beard says Indigenous young people are also four to six times more likely to be proceeded against by police
"(During 2010-11, Indigenous young people were) 8-11 times as likely to be proven guilty in a Children's Court; 14 times as likely to be under community-based supervision; and 18 times as likely to be in detention," Mr Beard says.
The report, Indigenous young people in the juvenile justice system, shows 58% of Indigenous young people under supervision during 2010-11 first entered supervision when they were aged 10-14, compared with less than one-third of non‑Indigenous young people.
"On average, Indigenous young people spent about 3 weeks longer (200 days compared with 178) under supervision during the year," Mr Beard says.
"'The report shows that 14-16% of Indigenous young people experienced supervision at some time when they were aged 10-17, compared with just over 1% of non-Indigenous young people."
However, over the five years to 2010-2011, there has been a slight drop in the level of Indigenous over-representation in the juvenile justice system.
Indigenous young people were 15 times as likely as non-Indigenous young people to be under supervision on an average day in 2010-11, down from 16 times as likely in 2006-07.
The largest fall in Indigenous over-representation was in detention, where the ratio dropped from 28 to 24 times as likely over the period.
The report also found Indigenous young people's over-representation increased as their level of involvement in the system became more serious.