The New South Wales Greens have announced plans to raise the age of criminal responsibility to 14 and to stop children under the age of 16 going to prison.

On Friday, ahead of next month's state election, the party released a justice policy including whole-government strategy reform, increased support programs for families and young people, a requirement for all police and youth detention centres to reduce harm on young offenders, and strengthened Indigenous-led justice reinvestment.

The Greens also committed to resource and develop transition plans to release all children under 16 from prison.

Currently in New South Wales children as young as 10 can face criminal prosecution and incarceration.

Last week Victorian Premier Dan Andrews' flagged raising the age from ten to 14 in his state if the national reform process was too slow.

In November last year the Northern Territory passed legislation raising the age of criminal responsibility to 12, which comes into effect later this year, and in the same month the ACT government announced it would raise the age to 12 in 2023 and to 14 by 2025.

In December, a national Council of Attorneys-General report made a "primary recommendation to increase the minimum age of criminal responsibility to 14 years without exceptions".

14 is the age of criminal responsibility recommended by the United Nations.

Greens Upper House MP and lawyer Sue Higginson said the current age of criminal responsibility is too young.

"Medical and legal experts are in fierce agreement that children are developmentally incapable of criminal responsibility and the age should be raised. Primary school aged children should not be in prison," she said.

"Other states and territories around the country are raising the age and it's time that we join them. It's disappointing that in spite of the evidence, we saw no progress on this issue in the last term of parliament.

"All evidence shows that children come in contact with the criminal justice system because of challenging life circumstances such as complex trauma, poverty, neglect and unaddressed mental or physical health problems."

Ms Higginson said the justice system "cannot continue to punish and imprison children because of the disadvantage they have suffered".

The Greens said the almost $150 million annual expenditure on youth justice in NSW, more than $700,000 per child in the system, is money spent in response largely to "crimes of poverty". The party said governments have a responsibility to support children and families in addressing underlying issues instead of criminalising trauma with a punitive approach.

Ms Higginson said a shift away from current measures locking kids up is particularly important for First Nations children who are drastically overrepresented in the system.

"More than half of the youth prison population in NSW are First Nations youth. We need a culturally appropriate response to youth offending that focuses on restoration and rehabilitation, not one that continues to take First Nations children from their families and communities and send them down a path of compounding trauma they may never be able to return from," she said.

Wiradjuri and Badu Island woman and Greens Upper House candidate Lynda-June Coe said the policy to raise the age "is a floor, not a ceiling to creating pathways for healing and justice for young mob".

"No 10 year-old child should be in prison. Raising the Age is one step we can take today to reduce the harms created by locking kids up," she said.

"Poverty and trauma are not crimes. Children are bearing the brunt of our communities collapsing under a system inherently built on prisons. This needs to change. Raising the Age is one crucial step to reform this punitive practice."

NSW Attorney General Mark Speakman told National Indigenous Times that the age of criminal responsibility is being considered and work is progressing at a national level by the Standing Council of Attorneys-General.

"Western Australia and the Commonwealth are co-chairs for this work," he said.

"NSW continues to support this work - noting that any reform in this area would need to be in the best interests of the community, with the safety of the community a key consideration. This includes the need for adequate processes and services for children who exhibit offending behaviour.

"The NSW Government is committed to using evidence-based interventions to reduce reoffending behaviour in young people."