The Principal Youth Court Judge says the potential for violent offending by young people needs to be anticipated earlier.
Judge Andrew Becroft's comment follows the release of a review of offending statistics over the 1992-2008 period that show an overall drop in the number of children being apprehended.
But instances of violent crime are increasing and Judge Becroft says that that is extremely concerning.
He says a small group of offenders needs more targeted earlier intervention, and recommends more family- and community-based programmes to help the children involved.
Those types of programme have already proved successful, he says.
Speeding up of process urged
Parliament's social services select committee has been hearing submissions on an inquiry into the identification, rehabilitation and care and protection of child offenders.
The Youth Justice Independent Advisory Group says that child offenders get help from government agencies like Child, Youth and Family as early as possible and that the family court process is simplified and speeded up.
A member of the group, Ian Lambie, says there are big gaps in services.
And Judge Tony Walsh, who sits in the Family Court, says social workers need to be involved in youth offending cases, as there are often big problems in the families that need to be addressed.
He says that currently police decide if care and protection is needed for a child offender, and that social workers should be involved in that.
Fewer arrests but more violent offending
Justice Ministry figures show that the number of children under the age of 16 being apprehended by the police has fallen since its peak in 1996 but that instances of violent offending have increased.
Although the figures show fewer children aged between 10 and 16 were apprehended from 1992 to 2008, the types of crime they were arrested for were more serious.
Property offences, including tagging, were the most common, accounting for 69% of apprehensions of children aged between 10 and 13 and 61% of arrests for those between 14 and 16.
But violence offences have increased, in particular in 2008, when the number of children under 16 arrested was 13% higher than the average over the entire time-frame being analysed.
The crimes were usually dealt with through the Youth Court, where 1200 children were convicted in 2008.
The most common outcome of Youth Court appearances remains a discharge without conviction.