One person has died in a serious crash in Northland this afternoon on State Highway One.

The crash involved a car and a prison van which had five prisoners on board.

One prisoner has moderate injuries, while there are also reports of minor injuries too.

A statement from Corrections says the prisoners are being transferred to another vehicle.

Police expect diversions to be in place for some time.

A St John spokeswoman has said four ambulances and one rescue helicopter were in attendance.