Sergeant Anthony Bond, of Dunedin, said the boy gained entry to the bus at Ocean View, started it up and then drove it from Brighton, via Green island and the Southern Motorway.
"He has gone through the centre of Dunedin taking the one way system, during the journey he has hit four vehicles and has been speeding and swerving in and out of traffic.
The boy was spoken to and referred to youth aid.
Police said last night nobody was in any of the parked vehicles and there were no injuries.
The first reports to police came in before 9pm.