Mr Osland said this was down to good policing, where the right targets were being identified and held to account in court, and the growth of community resilience and support.
"A lot of the key players within those southern communities have been actively targeted or apprehended and put on conditions to restrict their movements, and some have moved out of the area."
Martinborough ward councillor Julie Riddell said since the recent establishment of two youth groups in Featherston, there had been an influx of activities on offer for younger people to take part in.
"We have noticed a drop in local vandalism, graffiti and crime.
"This is a very positive outcome," she said.