Construction giant Lendlease has landed the federal government's $644 million major earthworks contract for the development of the Western Sydney airport at Badgerys Creek.

The announcement was made by the Prime Minister Scott Morrison on Sunday, who called the planned Western Sydney International Nancy-Bird Walton Airport a "game changer" for the area.

Mr Morrison said the contract was awarded to Lendlease Engineering and its joint venture partner CPB Contractors after a rigorous competitive tender process to undertake one of Australia’s largest ever infrastructure earthworks projects.

Conceptual render of Western Sydney Airport business park' Image: WSA Co .

Work under the contract would move around 25 million cubic metres of earth on the site to support construction of the major elements of the airport, including the runway and terminal.