A justice reform group is calling for 17-year-old offenders to be dealt with by the youth justice system rather than the adult criminal courts.
JustSpeak, a network of young justice system activists, called for the change in a open letter to Prime Minister John Key and senior justice sector ministers Judith Collins, Anne Tolley and Chester Borrows.
The open letter was signed by 150 people at the group's annual camp at Pipitea Marae in Wellington today.
There were about 10,000 apprehensions of 17-year-olds last year, so the change could make a difference to thousands of young people every year.
JustSpeak spokeswoman Lydia Nobbs said they could not vote, buy alcohol or tobacco, or enlist in the military without consent - but offenders were treated as adults within the criminal justice system.
"The basis for these laws is that until 18, it is not appropriate to treat 17-year-olds as adults because they need guidance and protection.
The same goes for the criminal justice system.
"Seventeen-year-olds shouldn't be tried in adult courts or held in adult prisons where they are exposed to more experienced offenders."
The open letter has support from Unicef, World Vision, YouthLaw, the Howard League for Penal Reform and a handful of youth law and criminology experts.
Ms Nobbs said including 17-year-olds in the youth justice system was broadly supported by justice sector groups and experts.
"New Zealand has a world leading youth justice system that is specifically designed to deal with young offenders. It holds young offenders accountable for their actions, while involving families in decisions and providing better options for rehabilitation.
"The evidence shows that the youth justice system gets better outcomes than the adult justice system for victims, offenders, their families and the wider community. It costs the taxpayer less than the adult system and means our communities are safer."
JustSpeak said it would build support for a policy change among non-governmental organisations, experts, and community and sporting leaders over the coming months, before presenting the letter to Mr Key and Justice Minister Collins, Police Minister Tolley and Courts Minister Borrows.