More than seven thousand people have been sent to prison following a conviction.
Ministry of Justice data shows the proportion of convicted charges leading to prison sentences has reached an all-time high at 27%.
People convicted of robbery, sexual offences, and homicides have the highest imprisonment rates.
Criminal defence lawyer Steve Cullen told Mike Hosking it's worrying to see such a large number of people involved in illegal activity.
He says it could be due to a wave of young people coming through, social media, or gang and drug influences.
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The Mike Hosking Breakfast