Auckland's main route to the airport will be getting a makeover in the new year.

The New Zealand Transport Agency's signed a contract with MHX Kirkbride Alliance to get the State Highway 20 A to airport project underway.

The new highway will deliver traffic straight to the airport, have a separate cycleway and provide for future bus shoulders and a future rail link.

Highway manager Brett Gliddon says it'll be a safer and more reliable route to the airport.

"You can expect some disruption over the next couple of years as we undertake this work, but the end result is it'll be a much better once the intersection's removed and the project's finished."