Australian infrastructure company Leighton Contractors has secured the contract to build the next stage of Auckland’s Western Ring Route.

The $70m project involves the upgrade of the Northwestern Motorway (State Highway 16) between the St Lukes Road and Great North Road interchanges.

The project will include widening of a 2km-long section of the motorway from three to four lanes in each direction. It is to be jointly funded by the New Zealand Transport Agency and Auckland Transport.

"The upgrade is part of our programme to get our network ready for when the Waterview tunnels are completed."

It will include improvements to the motorway ramps and the St Lukes Road to Great North Road intersection, as well as widening of the St Lukes Road overbridge spanning the motorway will to help drivers, walkers and cyclists.

Transport Agency highways manager Tommy Parker said: "The upgrade is part of our programme to get our network ready for the increased volume of traffic when the Waterview tunnels connecting the Northwestern and Southwestern (SH20) motorways are completed in early 2017."

Work on the latest project is scheduled to begin in mid-autumn, and will be completed by late 2016.

Other projects to connect the two motorways include the completed upgrade of the Maioro Street interchanges (SH20), and the upgrade of the Lincoln and Te Atatu interchanges, the Causeway Upgrade Project, and the Waterview Connection, which are all under construction.

As a ‘road of national significance’, the Western Ring Route will provide a 47km alternative to SH1 between Albany and Manukau, and will improve safety as well as city and regional transport connections.