Child advocates and legal rights groups are hopeful of soon forcing reform to the law which allows kids as young as 10 to be sent to jail.
Attorneys-general are due to meet in June to discuss changing the minimum age of criminal responsibility, following the close of public submissions to a review on Friday.
Save the Children says the minimum age should be 14.
"Putting children under the age of 14 through the criminal justice system is counter-productive to building safer communities, often trapping the child in a cycle of crime and disadvantage from which many never escape," the child rights agency's Matt Gardiner said.
Minimum age of criminal responsibility around the world. Source: SBS News
He said the solution lay in putting more money into helping children who had been abused or neglected, or were dealing with mental health difficulties.
Early intervention programs were delivering results.
Save the Children runs preventive, early intervention and diversionary initiatives in every state and the Northern Territory.
"We know that the younger a child is at their first sentence, the more likely they are to reoffend, including as an adult, and the severity of their offending is also likely to increase," Mr Gardiner said.
The Human Rights Law Centre said the existing law was out of step with medical science on child development and international human rights standards.
"Ten-year-old kids belong in schools and playgrounds, not in prisons, but Australia's outdated laws are being used to rip children from their families, community and culture and throwing them into concrete cells," said Shahleena Musk, acting legal director at the centre.
"Decent politicians would raise the age at which children can be locked up from 10 to 14."
Australia's age of responsibility is one of the lowest in the world.
