The issue was the subject of discussion at a meeting of state and federal attorneys-general in Adelaide on Friday amid calls for the age to be raised to bring Australia into line with international best practice.

Mr Porter said ultimately the issue would be one for public debate, following consultation with stakeholder groups and experts in criminal justice.

"There are a number of ways in which reform to change the age of criminal responsibility could be achieved," he said.

"It might be to lift the age up to 14 with no exceptions. In other jurisdictions, they make exceptions for very serious criminal offences.

"But in my personal observation, historically there have been instances where it has been appropriate to prosecute people who have been under the age of 14 for very serious offences."

The attorney-general said such prosecutions would depend on it being established the offender had the necessary mental capacity to understand the crime committed was both morally wrong and contrary to the law.

Ahead of Friday's meeting, a coalition of groups under the Change the Record banner placed more than 600 teddy bears on the steps of parliament house in Adelaide to acknowledge the number of young children locked up across the country on any given night.

Spokeswoman Cheryl Axelby said what was most alarming about that figure was that 70 per cent were Aboriginal and Torres Strait Islander children.

She said more money needed to be spent on support programs to assist children and families at risk.

"The biggest issue that we have is the criminalisation of families living in poverty," Ms Axelby said.

"It's about time we invested taxpayers' money at the front end instead of building more prisons and more youth detention centres where we're not actually creating stronger, resilient Australians; we're actually creating more traumatised and broken souls."

Australian Associated Press