Many of the offenders were from criminal families, had conduct disorders or had a lack of family support, Dunedin Youth Aid Sergeant Kevin Davidson said.
To make it on to the worst-offender list, the teenager had to be referred by Youth Aid and be a recidivist offender committing crimes across the board, including burglaries, car thefts and violence.
The unit, formed three months ago under the Government's scheme for 250 community police officers, is made up of two constables who report to Sgt Davidson.
It dealt with hardcore offenders in a bid to control and suppress their crimes, as well as find ways to break the cycle and prevent the teenagers from becoming life-time criminals, Sgt Davidson said.
Constable Jude Yeoman, of the Dunedin unit, said the aim was to redirect offending into constructive behaviour through sport, work and breaking the peer-group influence.
The unit took a holistic approach, often dealing with an offender's family, looking at the reasons behind the offending, what would motivate offenders to change, and where necessary, encouraging agencies to become more involved with families or offenders.
The approach was mainly proactive, but combined "old-school" policing methods, such as issuing search warrants and, in conjunction with other sections of the police, making arrests and following up after prosecutions, he said.
The unit's processes were similar to units in bigger cities, but its work was restricted by its limited staffing.
Christchurch, for example, had eight staff, including a sergeant and a detective.
The two-person unit in Invercargill worked closely with the CIB there.
Sgt Davidson said the unit seemed successful, so far.
One youth had gained employment and had managed to stay out of trouble after being told he could get a job on a dairy farm if his good behaviour continued.
The unit's size and function would be reviewed regularly.
"The object of the exercise is to reduce the effect of crime by deterring these young people away from offending.
"I'm a crusty old bugger and [the youth crime unit] is one of the few lights at the end of the tunnel I can see in relation to effectively dealing with kids and making an impact on their offending.
"We are not naive enough to think that because we have two extra guys that will be the end of that, but at least we have one more string to pull to dissuade those kids from that life of crime."
