A gang of Greymouth teenagers has been hunting down new people to town to try to pick fights, police say.
"Most of them are under the influence of alcohol. However, that is no excuse and we are not going to put up with this type of behaviour in our town," Sergeant Phil Barker said.
He said the group had been following people around trying to start punch-ups.
"The people being targeted are not locals and the offending group know this and are basically telling them they are not welcome in this town."
Some of those victimised were Tai Poutini Polytechnic students, he said.
"The students are here to learn and should not be treated with any disrespect - they have as much right to be in Greymouth as the troublemakers do.
"It's a brainless mentality.
"It's also not a good look for the town and others will be locked up if it continues."