Pine piles are forming the base for a State Highway 1 extension on Kahikatea Drive.

Hamilton's roads have gone to the logs.

The NZ Transport Agency is undertaking a $4million extension along the Kahikatea Drive part of State Highway 1 and more than a few mighty pine trees will be supporting it.

On completion the upgrade will rest on about 1500 pine piles, Hamilton City Council general manager infrastructure Chris Allen said.

Contractors Fulton Hogan have so far put 1300 of the piles into the ground, ranging in length from four to 13 metres, adding another layer of support for the roading which is being built on soft peat soil.

The piles will be capped in cement, then construction aggregate will be spread on top before the tar seal is laid down.

The project will add lights to the busy intersection where Gallagher Drive and Quentin Drive meet Kahikatea Drive.

The project is expected to be complete by mid-August.