PICTURE: Trampoline on car roof along Auckland's North Shore motorway

A professional furniture mover couldn't believe his eyes when he watched a trampoline strapped to the roof of a car speed past him on the Auckland motorway.

Tied down by two pieces of rope, it was considerably wider than the Suzuki Baleno it was strapped to on Sunday as it bounced along in the wind.

Brad Jackson, who was working at the time, told Fairfax the unconventional moving effort made his top five list of most bizarre ways to transport furniture.

"[The driver] wasn't going slow, every time she sped off and then stopped it was bouncing up."

"And she wouldn't have been able to get out of her car because the doors were tied shut to hold it down," Mr Jackson says.