Police are concerned that drugs are the motivation behind a recent burglary at the Dunedin Botanic Garden.

The garden's glasshouse has been broken into, and a surveillance camera stolen from inside.

Thieves have previously stolen cactus plants from the glasshouse, for their hallucinogenic properties.

And that's why the surveillance camera was installed.

Police believe thieves are again targeting cactus plants to make into drugs.

Certain types of cacti can be made into class A drugs.

No cactus plants were stolen in the recent burglary.

Police enquiries into the matter are continuing.