All were aged 16 and under.
Two faced more than one charge while some were co-accused.
Of the 12 young people facing aggravated robbery charges, seven were making their first appearances in the Youth Court.
"I am very concerned about that many cases in Kaikohe Youth Court. It's a very large number for one court to have in one day," Judge Walker said.
He has seen a similar number of cases in one day in the Youth Court in Manukau which, he said, has a far bigger population than Kaikohe.
Three Kaikohe youths were arrested two weeks ago after allegedly bashing and robbing a 16-year-old boy as he walked home from school.
That was the latest in a series of violent crimes that include armed robberies at Kaikohe McDonald's, Waipapa BP and a Kaikohe dairy.
All those arrested so far have been aged between 13 and 19, including two Kaikohe boys, one 14 and one 16, who have been charged with the aggravated robbery of the Tui Superette on Broadway early this month.
"We've got to understand what's driving these serious violent offences in Kaikohe without even beginning to fashion a solution to those problems," Judge Walker said.
"These examples of offending behaviour arises out of the community so it's everyone's responsibility and anyone that points a finger at others is abdicating his responsibility."
Judge Walker said the behaviour of some youths has been heavily entrenched over the years but was not impossible to change with the right systems in place, including early intervention.
"What we are seeing in New Zealand is an increase in violent offending, an increase in young girls offending, and things like neurodisability, autism, dyslexia, the effects of traumatic brain injury, and early onset of mental illness."
He said 16 cases were dealt with by each of the Youth Courts in Whangarei, Kaikohe and Kaikohe last month.
On the vacant Youth Aid supervisor's position in Kaikohe, Judge Walker hoped it would be filled as a matter of urgency as such officers in any area were an integral part of the system.
Northland police is involved in a number of joint initiatives with Nga Puhi Iwi Social Services, Kainga Ora, Place Based Initiative in Northland and other NGOs to address the underlying causes of serious youth offending.
Inspector Dean Robinson said for less serious or first-time offending, police Youth Aid officers worked closely with young offenders and provided options to address the cause of crimes.
"With a joint approach we can, and do, help young people find a route outside of crime."
In relation to young offenders committing robberies, he said detectives and constables who lived within Kaikohe were able to quickly identify and locate them, and deal with those offenders.
