Traffic has stalled as a section of State Highway 1 remains closed following a fatal crash south of Warkworth.
The two-vehicle crash was reported at 1.38pm on SH1, south of the Warkworth township.
One person was in critical condition but died at the scene.
Another person is in a serious condition after the crash and will be transported to hospital.
A Serious Crash Unit investigation is underway at the scene of the crash.
A section of of the highway is closed and diversions are in place for traffic heading north and south.
Police are advising motorists to plan ahead and expect delays on their journeys this afternoon.
Waka Kotahi is also encouraging people to delay their journey or expect long waits on the State Highway 16 detour route.
Kaukapakapa automotive repair shop owner Paul Martin said the traffic was never normally this bad on State Highway 16 on the Kaipara coast.
He expected it would take him a while to get home.