The new Young Serious Offender (YSO) declaration can be applied to teenagers between 14 and 17 who have committed two offences punishable by 10 years of imprisonment.
So-called YSOs may be sent to a military-style boot camp which is entering its pilot phase.
Minister for Children Karen Chhour said the boot camps will focus on discipline, physical activity, team building and being part of a group, and showing them they're capable of doing that and building up their self esteem.
The cost of pilot programme will be $5.1 million. Part of that is capital and the rest is staffing and training for the programme.
The government says they aim to reduce youth reoffending by 15 percent.
Meanwhile an additional 21 police officers will be redeployed in Auckland City, bringing the total number of beat police in the central city to 51 by the end of July.
It is the start of a staged two-year roll out, which will see 63 additional staff deployed in new Community Beat Teams across Auckland's three policing districts, with 17 in Wellington and 10 in Christchurch.
Andrew Coster, Commissioner of NZ Police, said some of those teams would start their rollout from July 1, bringing staff in from across Auckland so that there are 21 additional police in the CBD by the end of July.
The Wellington and Christchurch CBD rollout will come in the next 12 months as recruits come through the police college.
Police visibility can have a "dampening effect" on crime, he said.
"If police are more visible on the streets and people are feeling safe as a consequence, that's the result we're after," he said.
Police Minister Mark Mitchell was asked how they will recruit 500 more police, with so many moving to Australia.
Police have a plan, Mitchell said.
"There will be some who go to Oz but the majority will stay.
"The government will back them, give them the tools they need and support them to ... protect and serve their communities, that police are controlling the streets, not gangs."
The Prime Minister also said gang members should expect harsher penalties later this year.
Luxon said gang membership will become an aggravating factor in sentencing and gang patches will be banned in public.
He says the new rules will be passed in August and be in effect starting in November.
Luxon said three strikes legislation will be reinstated in November for serious crimes including sexual assault.
