Werriwa MP Anne Stanley has welcomed the state government's announcement confirming the final corridor for the South West Rail Link Extension.
"Now the government needs to get on with building it," Ms Stanley said.
"I have been calling for the extension of the South West Rail to the Western Sydney Airport since I was first elected."
The state government this week announced the final corridors to support the delivery of the proposed Sydney Metro-Western Sydney Airport project, South West Rail Link Extension and the Western Sydney Freight Line.
It will ensure the preservation of the South West Rail Link Extension Corridor which will run from the Aerotropolis through Kelvin Park and Rossmore to join the suburban rail network at Leppington.
It will link with the north south rail line corridor which will run from St Marys, with a tunnel to Orchard Hills, through to the new Western Sydney Airport, the Aerotropolis and Macarthur, with a tunnel from Oran Park.
The Western Sydney Freight Line Corridor will run from the future Outer Sydney Orbital at Luddenham through to the M7 at Horsley Park, where it will join a future section through Wetherill Park, which will link to the Southern Sydney Freight Line at Leightonfield, which connects to Port Botany.
However, no timeline has been provided for completion of the projects.
Community campaigner Michael Andjelkovic, who has been petitioning to extend the South West Rail line, said reserving the railway corridors is one thing but "actually providing the actual railway lines" is something else.
"It's all well and good for the NSW state government to make announcements but when will the projects actually be constructed?," he said.
"South Western Sydney are being denied rail access to the new airport and are being left in the dark about when rail access might be provided."
Transport minister Andrew Constance said the alignments would bring certainty to the western Sydney community and help drive investment around the new airport and broader Aerotropolis.
"Preserving these corridors for future passenger and freight transport links supports the development of the Western Parkland City, while planning for the needs of growing communities and industries to accommodate commuters, workers and businesses who all rely on different types of transport modes," Mr Constance said.
"Transport will play a huge role in shaping the way our communities move around in years to come, and we want to get this vision right, which is why we have spoken to the community at great length before finalising these future transport links."
Transport for NSW said all submissions received during community consultation were considered and adjustments were made to the final corridor alignments to minimise impacts to nearby residents.
Property owners have been notified and further details are being provided to them.