A truck has jack-knifed and is blocking all northbound lanes of Auckland's Southern Motorway.

Police were called at 2.25pm and the truck is blocking the entire north-bound lanes between Papakura and Takanini.

No one has been injured.

NZTA and the police were advising motorists avoid the area and to expect delays.

"Motorists heading south should expect some delays due to rubber-necking," NZTA said.

Detours are in place for north-bound motorists who are being told to use the Papakura off-ramp and travel via Great South Rd.

A crane was being organised to lift the trailer from the road, a police media spokesperson said.

"We ask them to be patient while we clear the scene."

Southbound traffic was still flowing.

- NZ Herald