Early intervention is seen as the key to reducing our prison population.

A new report's highlighting New Zealand's rising rates of incarceration, even though our crime rates are dropping. 

It suggests reducing prisoner numbers starts with targeting at-risk children, putting more money into intervention and addressing mental health rather than pouring more money into prisons.

Report author clinical psychologist Associate Professor Ian Lambie told Mike Hosking serious criminals need to be behind bars - but early intervention could prevent those crimes happening in the first place.

"If you went back and looked at the history of those people and looked at how their childhoods were, they are likely victims of abuse themselves. Evidence-based interventions for kids who suffer abuse and trauma look at keeping them at school, addressing their mental health needs and giving parents support they need."

Mr Lambie believes most of the worst criminal behaviour can be traced back to an abusive childhood. 

LISTEN TO THE FULL INTERVIEW WITH MIKE HOSKING ABOVE