The children's minister says she and colleagues decided against officials' advice about the best way to combat serious youth offending.
Papers show Oranga Tamariki warning that using legislation to set up a new 'Young Serious Offender' category is complicated, inflexible and risks teenagers glorifying the YSO label.
"A legislative YSO category may result in delayed court proceedings; young people glorifying the 'YSO' label (this occurred in Australia); and restricting or delaying the ability of the police and courts to access any strengthened powers to a narrow 'YSO cohort'," warned a single-page advisory from Oranga Tamariki (OT), which has been proactively released.
This would also require "significant and complicated legislative changes", and fixed criteria set in law for declaring a YSO - based on the risk of future reoffending - would likely be "too narrow and miss a high-risk cohort of young people".
Instead, they recommended a non-legislative approach would be more effective and work on more offenders.
But Karen Chhour told RNZ ministers rejected that.
"Ministers decided that a non-legislative approach did not provide the level of response necessary to address serious recidivist youth offending," she said in a statement on Tuesday.
The legislation coming in would let the police apply for a YSO declaration on teens who could then be sentenced to a boot camp.