The incident is being treated as arson. Photo: Kayla Hodge
Fire and Emergency New Zealand crews (Fenz) were called to the scene in an alleyway, next to the Iconix weighing systems building, in Thames Highway at 2am.
A Fenz spokesman said two crews from Oamaru worked to extinguish the caravan, which received extensive damage.
The building received minor damage on the outside, but there was no internal damage.
The fire was being treated as suspicious. A fire investigator was at the scene and working alongside police, the spokesman said.
Sergeant Tony Woodbridge, of Oamaru, asked anyone with information to contact police.
