Police are concerned about increasing disorder in and around the Dunedin Botanic Garden.

An administration building window was smashed on Monday night, although nothing inside was reported stolen.

It follows reports of people drinking and causing disturbances in the public space recently.

Police are worried there could be a resurgence of student drinking games being played in the reserve.

That was a problem several years ago, when intoxicated people were falling out of trees.

The facility's also been targeted by thieves previously, who've broken into the hot house to take cacti.

It's legal to drink alcohol in the garden.