Three girls are now in the youth justice system after a fatal stabbing in Hamilton on Saturday night - a system designed to recognise the vulnerability of young people.
A 15-year-old and a 13-year-old appeared in the Hamilton Youth Court on Saturday charged with aggravated wounding and unlawfully interfering with a motor vehicle, while a 12-year-old was referred to Youth Aid on an unlawfully interfering charge.
Police have launched a homicide investigation into the the death of Norman Kingi, 54, who was stabbed on Ranui St in Hamilton on Friday night, about 11.30pm.
Children in law are those aged 10-13 and youths are 14-17. Once people turn 17 they are treated as adults by the criminal justice system.
Under changes announced by justice minister Amy Adams and social development minister Anne Tolley in December, the age has been raised to 18 for some offenders.
This will apply from 2019 but only to teenagers who commit low-level offences while those who commit serious crimes will continue to be heard in adult courts.
Other changes mean serious offenders aged 14 to 17 can be transferred to the adult jurisdiction at a judge's discretion.
In recent years, the number of youth defendants convicted and sentenced in an adult court has fallen - from 336 in 2010 to 96 in 2016.StatsNZ
Last year, the youth jurisdiction made 1989 decisions, known as 'outcomes'.
If the offence is murder, or manslaughter, a young person is automatically transferred to the adult jurisdiction.
Statistics show a handful of young people are convicted and sentenced in court each year for homicide 'and related offences'. Last year, three young people were convicted in this category.
A report by the Ministry of Social Development in September last year found an estimated one in 20 children offend.
It is rare for young people to commit serious offending - less than one per cent of those born in 1999 committed an offence before turning 14.
Children under 10 cannot be held criminally responsible and, therefore, cannot be prosecuted.
A drop in youth offending during the 2010s is not unique to New Zealand.
The causes are still being debated but it's thought a combination of changes to police procedures, more effective youth justice, and better security are factors, the report says.
Last year, two teenagers who robbed and murdered a 54-year-old man at an Auckland motel were sentenced to life in prison.
Leonard Nattrass-Berquist and Beauen Wallace-Loretz were 17 when they attacked Ihaia Gillan-Harris at the Epsom Ascot Motel, two days after Christmas in 2014.