NZTA has chosen to keep State Highway One on its existing route between Whangarei and Port Marsden

The current 22 kilometre route will be expanded to four lanes, and some sections will be built on a new alignment to straighten out any curves.

There will also be a separated walking and cycling path.

The Transport Agency had also been considering building the highway to the west, to avoid the coastal marine environment at Oakleigh.

But the existing route received strong support during public consultation.