Police say pipe bombs found next to Auckland's Southern Motorway yesterday, were capable of causing deadly harm

Officers were called to a walkway at Highbrook about 11.30am - finding a deceased and the two devices.

A section of State Highway One was closed for hours.

Police say staff had to balance public safety considerations and maintaining the scene's integrity - when they shut down the road.

They say the devices have been destroyed and a post-mortem examination of the man should be completed today.