They are urging the Mataura community to report any issue, no matter how minor.
Last month, the Gore District Council announced it was closing the library and service centre at 2.30pm daily until further notice.
That was because of safety concerns for staff and the public caused by antisocial behaviour from youth.
Sergeant Eric Browne, of Gore, said the increase in police patrols was because of the situation.
Police had met library and council staff to discuss strategies.
"We’ve been dealing with youth consistently in Mataura for quite a while. It’s not something new," he said.
"I think the general feeling in the community is that they are sick of the youth problems."
Since the library changed its operating hours, an increase in reported incidents had not been noticed, he said.
Police dealt with a lot of incidents both minor and major in Mataura.
The current situation highlighted that many incidents in the community were not reported to police.
"We just really need the community to report things, no matter how minor they seem."
The Mataura Police Station was manned by two police officers who worked opposing shifts, he said.
"Due to the nature of the job we don’t have a staff member in the police station all the time because that one cop could be out doing jobs."
However, there was a phone outside the station that automatically dialled the police number.
"But the most effective way to get a hold of us if we’re not at the police station is to call 105 or 111."
