Evidence, rather than "uninformed or deliberately misconstrued narratives," is needed to drive policy around youth justice, a senate hearing has been told.

Appearing in front of an inquiry into Australia's youth justice and incarceration system, Australia's Children's Commissioners, Guardians and Advocates said the public policy which has focussed on "punitive" 'tough on crime' measures towards children does nothing to help public safety.

"In what other first world country, do we see children dying in custody?" Jacqueline McGowan-Jones, WA's Commissioner for Children and Young People, asked the committee.

"In what first world nation do we think it's reasonable that we detain children in cells for up to 23 hours a day, that we leave them in great need, and they die in a system that should be protecting them."

The evidence comes less than a week after the latest Productivity Commission data revealed an increase in the number and rate of Indigenous children and young people incarcerated in Australia.

They called for people to listen to the evidence, noting several jurisdictions had actively gone against medical, legal, Indigenous, and human rights evidence to enable punitive responses in youth justice.

"We cannot simply drive down the same road as we always have, because we will inevitably end up in the same location," South Australia's Guardian for Children and Young People, Shona Reid, said.

In the Northern Territory, where the age of criminal responsibility has been reduced to 10-years-of-age, and the presumption of bail removed, the NT's Children's Commissioner, Shahleena Musk, said the system was "geared more towards incarcerating children than investing in earlier supports and interventions, diversionary and restorative justice programs, accommodation and rehabilitative alternatives".

"What is happening here in the Northern Territory reflects the politicisation of youth crime and any social behaviour by children on the back of hypervigilant and sensationalist media and social media reporting too often framed in stereotypical and derogatory narratives about Aboriginal children," Commissioner Musk said.

The Senate inquiry was set up in the wake of the second young person to die in youth custody in WA in less than a year, with over hundred organisations and experts calling for changes to systems across the country.

In October 2023, 16-year-old Cleveland Dodd took his own life in the Unit 18 youth detention facility at Perth's Casuarina Prison. The Aboriginal teenager was the first child to die in custody in Australia in more than a decade, and the first in WA history.

"Australia has administrative standards for youth justice signed by every jurisdiction, and it says, 'they're nice to have,'" Commissioner McGowan-Jones said. "They're not nice to have. They are critical for the well-being of the children who are in contact with the youth justice system and particularly those incarcerated.

In Queensland, where the state has suspended the Human Rights Act three times in two years, Child and Family Commissioner Natalie Lewis said the state found itself in policy environment "characterised by sweeping legislative reform" in response to a number of public incidents, while simultaneously "ignoring well known evidence and discarding long standing and universally accepted principles of rights and justice".

"There have been a series of policy changes, largely and increasingly punitive in nature," she said, arguing children in Queensland "have less protections than adults do".

The federal government has routinely highlighted the state's responsibility for youth justice, but Commissioner Lewis told the inquiry this was no longer an option.

"The Commonwealth can and should take responsibility for limiting how far that pendulum can swing in any jurisdiction at any given time," she said.

"The impacts of that [youth justice] legislation on children and young people, and on community safety, should be of keen and ongoing interest to the Commonwealth, especially given that those outcomes are integrally linked to Australia's obligations as per international law.'

Commissioner McGowan-Jones said Australia needed solutions which "reflect what children and young people tell us or work for them".

"We must individualise responses…given the significant over-representation of Aboriginal and Torres Strait Islander children in the criminal justice system; In fact, I would prefer to call it a legal system, because there is not much justice involved for children."

In finalising her statement to the inquiry, NSW's Advocate for Children and Young People, Zoë Robinson, said children she had spoken to in custody had told her, "The only way you get heard is to yell and scream."

"So here we are as commissioners, guardians and advocates for all the children across this country, yelling and screaming," Ms Robinson said.