The Transport Agency is putting forward its case to build a highway connecting Auckland and Northland.
The Puhoi-to-Warkworth highway would cost more than $750 million to build.
The Transport Agency told a hearing in Auckland the proposed highway has broad support from local iwi, Auckland Council and business groups.
It said the road is a logical next step to making sure goods and people can travel efficiently and safely between Auckland and Northland, and would support the projected rapid population growth for Auckland and Warkworth.
A board of inquiry set up especially for the project will hear submissions over 14 days.