MORE than half the children who commit a crime are reconvicted within a decade - most on multiple occasions - highlighting a fundamental failing in the juvenile justice system.

A Herald investigation also reveals that assaults by juveniles have soared, with domestic violence cases by 10- to 17-year-olds rising 167 per cent between 2001 and 2010. Non-domestic violence assault rose 20.4 per cent, according to data provided by the NSW Bureau of Crime Statistics and Research.

As the dramatic shooting of two youths driving a car along a Kings Cross footpath last weekend continues to reverberate, there have been calls for an overhaul of the juvenile justice system.

A 10-year reoffending study casts serious doubts on the long-held assumption that children grow out of crime if they are diverted from courts with cautions or youth justice conferencing, which puts young offenders face-to-face with their victims.

The study, provided exclusively to the Herald, shows 54 per cent of 4938 juveniles who came into contact with police in 1999 were convicted again within 10 years. Of those, the offender was, on average, convicted again four times.