A Fire and Emergency New Zealand (Fenz) spokesman said they received reports of a garage fire in the suburb of Kew at approximately 3.45pm.
When crews arrived it was deemed a small property fire but had since escalated.
A second alarm was raised and two additional trucks were sent from the Dunedin City and Roslyn stations.
Crews were speaking with a fire investigator but it was unclear if one had attended the scene, the spokesman said.
"At this stage it is not being treated as suspicious."
The fire had since been extinguished at 5.15pm.