A coalition government wouldn't fund urban rail projects in Western Australia and would instead back roads, Opposition Leader Tony Abbott has confirmed.

The WA Liberals revealed during their state election campaign earlier this year that they hoped the Commonwealth would pay 80 per cent of the $1.89 billion airport rail link project and 50 per cent of the $1.8 billion MAX light rail project.

In April, Mr Abbott appeared to dash Mr Barnett's hopes by saying his party had "no history" of funding urban rail.

And on Thursday, he confirmed the state would get no funds for rail if the coalition wins the election.

However, it would continue funding the Gateway road upgrade project surrounding the airport.

"I'm also talking to the Premier about some other major road infrastructure projects in WA and I'll have more to say about them in the run-up to the election," he told reporters in Mandurah, south of Perth.

"If we can give more support to major road projects, that obviously makes it easier for the state government to invest in significant rail projects.

"They're owned by the states, they're run by the states, and that's why I think they are fundamentally a state responsibility."

Mr Barnett conceded it would be harder to get the rail projects up without federal funding, but they would still be done.

"It's all good stuff. Which bucket it goes into doesn't really matter, as long as we get a strong commitment on transport."