All three have appeared in the Oamaru District Court and have yet to be sentenced.
Smith said landowners took the issue seriously, and communicated with each other quickly if suspicions were aroused.
"They've got a pretty good network really, through the whole Lindis Pass area, where they will check out suspicious vehicles and talk to each other.
"There hasn't been an increase in incidents as such. I think there's probably ... more farmers aware and they are talking to each other a lot more. That all helps."
Recreational hunting for deer and pigs was a popular pastime in the areas and hunters generally abided by regulations, he said.
Senior Constable Peter Scott, of Kurow, said he had not had any incidents reported recently.
But he often reminded people of their obligations related to hunting.
"It's really been a question of education up here with so many contractors and people new to the area with various projects going on."