An alliance led by construction giant Leighton Holdings is set to deliver a transformational Perth road project in Western Australia after finalising an agreement with the state government body charged with overseeing major road projects.

Leighton Contractors Pty Ltd, a subsidiary of Leighton Holdings, announced earlier this week that the Gateway WA Alliance in which it has a 68 per cent stake had reached an agreement with Main Roads WA on the price, scope and construction methodology for the Gateway WA Perth Airport and Freight Access

The contract cost for the project is set at $899 million.

Set to be the largest ever development undertaken by Main Roads WA, the project involves major upgrades to the road network surrounding the Perth Airport and the freight and industrial hubs of Kewdale and Forrestfield.

Features include extra lanes on Tonkin Highway, new interchanges and the upgrade of Leach Highway to an expressway.

The upgrade is expected to provide greater transport capacity to accommodate anticipated increases in traffic from a planned upgrade of the airport and improve operational efficiency of vehicles servicing the international freight terminals.

Construction will be performed in stages so as to minimise traffic disruption.

Early works on the first stage of the project, which are expected to cut 3.7 kilometres off the current transport route for trucks by providing a direct link for heavy transport to the regional network via Tonkin Highway southbound, started in February and involve an on-ramp to the Tonkin Highway from Abernathy Road.

Transport Minister Troy Buswell says the importance of the project cannot be understated.

“Gateway WA is a commitment to a massive road network upgrade in one of the State’s most important transport hubs around the Perth airports and the nearby Kewdale and Forrestfield industrial areas which will be delivered by early 2017,” he says.

“It will not only reduce traffic congestion for Perth road users, but will benefit those West Australians in regional communities who depend on a thriving resources industry for their livelihood.”

Apart from Leighton, other members of the Gateway Alliance include Georgiou, GHD, AECOM and BG&E.

The alliance was awarded the project to upgrade the Perth Airport and freight access in November last year.

Completion of the Gateway project is scheduled for 2017.