Australia’s biggest transportation project is set to begin, with the New South Wales (NSW) government submitting the initial planning application for the $11.5bn WestConnex motorway.

This move comes after the state approved the business case which revealed that the project will deliver major benefits NSW economy and the motorists of Western Sydney

WestConnex project will connect western and south Western Sydney with the city, airport and port in a 33km continuous motorway.

NSW’s Premier, Barry O’Farrell, said WestConnex would ease congestion, deliver liveable and connected communities and create jobs across Sydney.

"WestConnex is a game-changer for Sydney. It will save motorists time by making travel between Sydney’s west and the east easier," O’Farrell said.

Works under the proposed project will be executed in three stages, with the first stage scheduled to be complete in 2017.

"WestConnex will inject $20 billion into the NSW economy, including hundreds of apprenticeships for young people."

The first stage will include a widened M4 to four lanes in each direction from Church Street, Parramatta to Homebush Bay Drive, Homebush as well as an extension of the M4 through twin three lane tunnels under the Parramatta Road corridor to Parramatta Road and City West Link, Haberfield.

The planned motorway will help travellers avoid up to 52 sets of traffic lights, saving about 40-minute travel time between Parramatta and Sydney Airport, and reducing the travel time from Parramatta to the CBD to 25 minutes.

"WestConnex will inject $20 billion into the NSW economy, including 10,000 construction jobs and hundreds of apprenticeships for young people," O’Farrell said.

The road will remove up to 3,000 trucks per day from Parramatta Road and put them in underground tunnels, returning the surface roads and land uses to regional communities.