The Liberal Party has promised to build a multi-storey car park at the Edgewater train station if it wins the state election.

The Transport Minister Troy Buswell says the 1,000 bay facility would cost $47 million to build but commuters would not be charged more than the current fee of $2 a day.

"Of course there is a broader cost that taxpayers will pick up in terms of the capital asset," he said.

"But I have to stress, that we do that with public transport all the time. We only collect about 25 per cent of operating the public transport system at the fare box.

"The question's asked, Does that mean the taxpayer is subsidising public transport? The answer is yes, taxpayers have always and will always subsidise public transport here in Perth."

The Premier Colin Barnett says the key to encouraging more people to use public transport is having more car bays.

"One of the key issues for people using our train service is trying to get a parking bay at a train station," he said.

"As the population grows, as the use of public transport grows, there is a shortage of parking bays at our major train stations."

Mr Barnett has dismissed Labor's policy to trial the use of satellite car parks with shuttle buses running to nearby train stations as 'bizarre'.

"People won't do that," he said.

"You've also got to ask the question, what happens to parking at sporting grounds when people want to turn up for netball or football training? Those are mainly local government parking areas built for recreational facilities."

Labor's Transport spokesman, Ken Travers has described the approach as 'piecemeal'.

"This is not a response to the congestion that we're facing," he said.

"What you need is an integrated plan to address congestion.

"Labor has that with our Metronet.

"Mr Barnett, and I assume we will get more of these announcements in the coming weeks, has a piecemeal approach."

The issue of multi-storey car parks turned political last month when the Opposition criticised Liberal Party candidates Jan Norberger and David Goode for distributing flyers which said they were pushing for the facilities.

Mr Travers pointed to evidence given to a Parliamentary committee by the head of the Public Transport Authority Reece Waldock last year.

Mr Waldock told the committee such a facility would cost the government $20 per bay each day to run and said he could not see how they could justify the subsidy.

Mr Travers also accused the candidates of making false promises when the Liberal Party had not yet endorsed the idea.

Mr Norberger has argued for the Edgewater facility and was by the Premier's side as he made the announcement.

Mr Buswell would not say whether Mr Goode's preferred location of the Thornlie station will be considered.

"We will look at other multi-storey car parks over time but we think it's important to start somewhere," he said.

'We've been having some preliminary looks at stations like Stirling, a little bit closer to Perth, down at Murdoch and on some of the heritage railways."

But the State Opposition says the Edgewater proposal would create more traffic congestion around the station.