There are warnings of big delays for morning commuters heading north of Auckland on State Highway One.

A person has died in a car crash near Warkworth in a collision that's left four others hurt.

Two of the survivors are in serious conditions.

The two-car crash happened around 4.50am, just south of Warkworth.

One of the two cars involved was left down a bank after the crash.

Police are warning of considerable disruption.