Leaked confidential plans for a second Sydney airport show the project would be the largest earth-moving project in Australian history since the Snowy Mountains scheme.

According to a Daily Telegraph report, construction of the airport will begin next year and will occupy a site of more than 20 square kilometres at Badgerys Creek.

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The first stage is expected to be completed by 2023, while the second stage, which includes a train line and twin runways, will be completed by 2050.

Travel to and from the proposed airport could become a major issue however, with Badgerys Creek located 51km from the Sydney CBD.

Sydney Kingsford Smith Airport is only 8km from the city, while Melbourne’s Tullamarine, long bemoaned for being too far from the city, is only 23km from the CBD.

The Badgerys Creek site will be much further from the CBD than the current airport.

The airport will reportedly cost $4 billion and when complete, will process 80 million passengers a year – double the amount which passes through Sydney’s current airport.

The plan is understood to have been handed to the Abbott government in February this year and involves the excavation of more than 100 million cubic metres of earth.

According to the report, the city’s second airport will feature twin parallel runways which are based on world best design for quicker loading and departures.

The project is expected to create thousands of jobs for Sydney’s west in just excavation work alone.