He asked what happened to those involved in ram raids aged under 13 - below the age of criminal responsibility - and those older.
He also questioned the validity of statistics showing a drop in youth crime, asking if there was a "don't ask don't tell situation" masking the reality.
National Party police spokesman Mark Mitchell said without police having a "strong response" they risked diminished public confidence in not only police but the justice system.
Assistant Police Commissioner Chris de Wattignar said there had been "very real drop off in actual offending".
He said based on victim surveys the number of reported crimes to police had remained relatively stable.
He said rather than poor recording their methods had improved greatly, and there were multiple ways youth crime was reported to police - including through schools and youth workers.
"A lot more of that data is now being picked up and our youth aid officers receive those files and make those decisions based on what the frontline has seen.
"So I'm fairly confident that we are still recording the actual youth crime.
"But what we're seeing is a shift into more of those alternative actions, rather than going straight to the youth court."
Oranga Tamariki youth justice system director Ben Hannifin said while overall youth crime was trending down there had been a spike over the past year.
They had seen a 14 per cent increase in police proceedings - including 24 per cent increase for those aged under 13 and 11 per cent for 14-17 year olds.
Auckland was a "specific concern", as was a spike in more serious, violent offending - including ram raids, he said.
Hannifin said their "twofold" approach focused on stopping youth "getting tough in the first place" and intervening early, particularly with those aged under 13.
Hannifin said under the programme Kotahi te Whakaaro in Auckland, Oranga Tamariki, police and other agencies met each morning to discuss any youth offending issues.
If there had been an incident overnight within 24 hours they had "wrap-around" support for the young person and their family.
Hannifin said this approach was working and urged politicians to continue to fund and expand it beyond the recent surge in youth crime.
"We are are seeing results... and having some really good impacts on a lot of kids."
De Wattignar backed this call along with wider funding resources for intervention and community support.
"My wish list would be that we were able to make that happen as an ongoing and enduring process.
"It speeds up the intervention. We can catch those kids' cases the next morning and start working."
For those aged over 14 and committing the more serious crimes, including aggravated robbery, Hannifin said youth residences remained an option and there were "greater numbers" coming into them.
Normally there were be about 95 to 105 children in those facilities, while currently there were 120.
But Hannifin said simply locking these children up didn't address the core problems, and some even forged stronger criminal connections in those facilities.
Almost all of the children involved in recent wave of ram raids and crime had come from homes with family violence, he said.
About 70 per cent had been around family violence by the age of 3.
"They're growing up in an environment where they're not safe, where they are being hurt, in all measures of abuse, neglect, sexual abuse, physical abuse.
"And then on top of that... is the high propensity of mental health problems, three times more likely to have a brain concern.
"Almost all of them are out of school, from a home with financial stress, from an environment where the attitude to offending and offending behaviour is the norm."
