A section of Auckland’s Southern Motorway is closed and a person is in a critical condition after a serious truck, van and car smash.

Police responded to the three-vehicle crash between Papakura and Takanini around 9.40am.

All northbound lanes were closed at 10am while emergency services responded to the accident.

Motorists are being warned to expect delays and diversions.

Around 11am New Zealand Transport Agency Waka Kotahi said police would shortly open one northbound lane to allow traffic stuck within the closure to pass through.

All other traffic is being advised that they must exit at Papakura.

A police spokesperson said early indications suggest one person is critically injured.

“Due to a serious crash, all northbound lanes between Papakura and Takanini are now closed,” New Zealand Transport Agency Waka Kotahi said.

“Please avoid this route or expect delays.”

St John said they responded to the crash with six vehicles and transport to hospital was not required.

Northbound traffic is being diverted via Great South Rd while southbound lanes remain open.

Traffic is gridlocked on the motorway between Takanini and Drury, with motorists now sitting in an 8km-long queue.

The Serious Crash Unit has been advised.

A large truck can be seen parked to the side of the motorway and people in the mangroves next to it. Photos suggest a car has come off the road.

The crash scene on Auckland's Southern motorway.