The NZ Transport Agency said the incident happened at 7.30am. Wet weather conditions are not making things easier and motorists are being told to take extra care and to expect delays.
Traffic is also heavy from Oteha Valley Rd through to Esmonde Rd, the NZTA said at 7.30am. Northbound traffic is flowing well.
A crash on the Southern Motorway, after Takanini, also caused delays shortly before 6.30am. The crash has been cleared, but congestion is still heavy in that area.
Images from the NZ Transport Agency cameras show the crash was blocking the right citybound lane between the Hill Rd and Manurewa-Takanini onramps.
Motorists were told: "Merge left with care to pass and expect delays."
A police spokeswoman said several people had called to report the nose-to-tail collision about 6.25am.
Police were at the scene, she said. It appeared all those involved were out of the vehicles and had not been injured.
Northbound traffic on the Southern Motorway remains heavy from Drury through to Papakura and also through Te Irirangi Drive to Greenlane.
People heading southbound will be relieved to know traffic is fine there.
Motorists heading into the city from West Auckland can expect heavy traffic from Hobsonville through to Royal Rd on the Northwestern Motorway and again from Te Atatu Road to St Lukes.
Northbound traffic is flowing smoothly.
On the Southwestern Motorway (SH20), traffic is heavy from Hillsborough and northbound traffic is heavy from Lambie Drive through to Massey Rd.
Anyone on the Upper Harbour Motorway (SH18) can expect moderate congestion from Greenhithe Rd through to Paul Matthews Rd. While westbound traffic is flowing well.
