Labor leader Michael Daley has committed to spending $8 billion to "fast-track" the Sydney Metro West project between Parramatta and the CBD, in an election pitch designed to resonate with voters in vulnerable seats in Sydney's west.
However, Mr Daley would not nominate a completion date for the project, but instead said a Labor government would "at least match" the government's promise to have the line open by the late 2020s.
"Our hope is that we will get it done more quickly," Mr Daley said.
"A Daley Labor government has $8 billion set aside now to make the West Metro not only our top transport priority but make it a reality.
"These projects can be delivered much more quickly if you have a big upfront injection," he said.
The $8 billion includes $3 billion already committed to the project by federal Opposition Leader Bill Shorten to the Western Sydney Airport rail project, should Labor win government at the federal election.
Mr Daley said Labor, if elected to government at the March 23 state election, would also spend $3 billion upgrading Sydney's existing rail network.
Announcing the policies at a lunch hosted by the Western Sydney Business Chamber, Mr Daley said his policies were "modest, real, affordable, costed and focused on people".
When it first announced the Metro West project in late 2016, the Coalition government said it wanted construction of the line for single-deck trains to start within five years – or by 2021 – and for the line to open in the second half of the 2020s.
NSW Transport Minister Andrew Constance last month vowed that project's construction would be "well under way" in the next term of government if the Coalition was re-elected.
Labor's promised investment is almost triple the funding allocated by the Berejiklian government, which earmarked $3 billion for the Metro West in last year's state budget.
Transport for NSW has estimated the project will cost up to $18 billion. The final construction cost will depend on the route chosen.
Mr Daley said the $3 billion for Sydney's existing rail network would be guided by a board of experts to increase services and improve reliability.
"Trains are running late, the system can't cope with increased demand and the public can no longer rely on government to deliver to deliver a basic service," he said.
Mr Daley's rail commitments were accompanied by a number of other transport announcements, including a promised to spend $900 million improving regional and rural roads, and a further $1.1 billion expanding the government's $825 million Pinch Point Program, which aims to ease congestion on Sydney's major roads.
He also promised to give $10 million to Liverpool council to undertake a feasibility study and prepare a business case for a rapid transport system between the Western Sydney Airport and the city's south-west.
Lisa Visentin is a state political reporter at The Sydney Morning Herald.