The NSW coalition will more than double its funding for a western Sydney metro if it wins this month's election, with a promise to start construction next year.
NSW Premier Gladys Berejiklian on Sunday promised an extra $3.4 billion to the Metro West project, taking the state funding to $6.4 billion.
Ms Berejiklian said her government would begin construction of the project in 2020, with tunnelling expected to begin in Westmead in 2021.
The NSW Labor opposition has promised $5 billion towards the project, with another $3 billion from the federal government if Bill Shorten wins the May election.
NSW Labor leader Michael Daley said he would complete the project, which will run from the CBD to Sydney's west, faster than the government.
But Transport Minister Andrew Constance said there was no way Labor could build the metro any faster.
"You can't build it any quicker, even if you tried," Mr Constance told reporters in Westmead, where the Liberal Party unveiled its big, blue, bespoke "Gladys" election bus.
"Unlike Labor, we are putting the money in, we're not waiting around for fictitious federal funds."
He said Labor's plan to hold parliamentary inquiries into infrastructure projects over $1 billion would delay the metro.
Mr Constance wouldn't provide an overall cost estimate on the metro, which he said would take commuters from Sydney to Parramatta in 20 minutes.
The project will take about eight years to complete and has reportedly been estimated to cost $18 billion.
While most of the line will be underground, Mr Constance confirmed some homes would need to be compulsorily acquired by the government.
Ms Berejiklian responded to reports her sister Mary had told online critics of the premier to "grow some pubes" on Instagram.
"I'm sure every family has a Mary, and you can tell her to tone it down but that's just Mary," Ms Berejiklian said.
"I said 'Mary tone it down and she goes 'whatever,' so you know, that's just Mary."
While the coalition was in western Sydney, Mr Daley was at Allianz Stadium promising $95 million to a community sports package.
The money would be used to upgrade community sporting facilities across NSW.
"While the Berejiklian Government gives major stadiums a golden hand out, Labor will give local sports a helpful hand up," Mr Daley said in a statement.
The NSW election is on March 23.
