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…