Emergency services were called to the suspicious fire at 6.40am today.
Police and Fire and Emergency NZ were notified of a car on the back of a trailer that had been set alight outside a Derwent St property in the suburb of Glengarry.
The blaze was extinguished and police made inquiries with neighbours.
The investigation is continuing.
A resident of the property next to the vehicle said they were its owner.
They said they woke to the sound of a motorbike outside their home sometime after 6am and a neighbour called emergency services.
While firefighters put out the blaze, the resident said they noticed a can of petrol left on the side of the road.
They said the vehicle had just been returned after having been stolen over a week ago.
- By Ben Tomsett