Police are hunting a "bunch of idiots" after five cars were rolled on to their roofs in Palmerston North overnight.

The cars were found upside down on Pacific Drive, Benmore Avenue, Kaimanawa Street, Church Street and Ruahine Street, covering a distance of more than 10km.

"It's all round town, it's bloody madness," a police spokesman in Palmerston North said.

"Instead of chucking rocks through their windows, now they're just tipping them on their roofs."

This was the first time he had seen such a case in the city, the spokesman said.

"This is a phenomenon from last night. It's a bunch of idiots, I'd say."

None of the cars had been robbed. It was not clear what time the vandals had struck.

- NZPA