Queensland has the most children behind bars in the country and its youth detention system is failing "significantly".
The Child Death Review Board delivered the damning assessment on Thursday, saying the detention system set up to address juvenile offenders' behaviour has instead led to a "cycle of incarceration" for some.
In an annual report tabled to state parliament, the board said it reviewed 60 of 72 juvenile deaths known to the child protection system in 2022/23.
Six deaths were in the Queensland youth justice system.
A case study of two Indigenous boys who died after spending considerable time in the detention system found their deaths were preventable.
The boys had spent a combined 600 days in detention.
Both children had upbringings exposed to violence, alcohol, drugs, abuse, neglect and family separations or disconnection.
The board said their experiences in detention "served to cause further trauma, disconnection and hopelessness".
"It is not acceptable for any system to fail in its intent so significantly," chairman Luke Twyford said in the annual report.
"It highlights that our current model of detention is not working as intended."
The board said it sought to understand how contact with the youth justice system led to a "negative cycle" for some offenders.
"Children and young people need a youth justice system that can provide trauma-informed responses to address their underlying beliefs and behaviours," it said.
"Instead, we have a system that can too easily fall into providing a negative cycle of more punitive practices and escalating behaviours that trap young people into anti-social and risk-taking behaviours that led to a cycle of incarceration."
The annual report also revealed Queensland locked up more children than the rest of the country.
On an average day in 2022, 267 Queensland young people aged 10-17 years were in youth justice custody.
Another 256 were in a youth detention centre and 227 spent time in a youth detention centre on unsentenced detention.
In 2021/2022, Queensland children spent a total of 100,425 nights in custody compared with 68,172 in NSW.
More than a third of the national nights in custody spent by children were in Queensland.
First Nations children were significantly over-represented, with 64 per cent of 10- to 17-year-olds under youth justice supervision and 66 per cent in detention identified as Indigenous in 2021-22.
The report says Indigenous people aged 10-17 are 21 times more likely than non-Indigenous juveniles to be under youth justice supervision and 23 times more likely to be in detention than their non-Indigenous people.
In response to a youth crime outcry and capacity issues, the state government is building two new detention centres in Queensland.
It comes after controversial laws were passed in 2023 allowing contingencies for police watch houses and adult prisons to be used as youth detention centres, overriding the state's Human Rights Act.
The contingencies can only be used in extraordinary circumstances until the Woodford and Cairns detention centres are complete in 2026 and 2027.
