A lack of support from federal Opposition Leader Tony Abbott could see Colin Barnett's transport projects being placed on the back burner.

Mr Abbott indicated on Thursday that it would be unlikely funding would be given to state rail projects, should he become Prime Minister.

Tony Abbott said the primary focus on transport funding would be roads should he become Prime Minister.

Commonwealth funding had been included in the West Australian Liberal Party's budgeting of big-ticket projects for 2018, in the lead up to the state election, including the MAX light rail and Perth Airport rail link.

In response to questions about funding rail projects in Melbourne, Mr Abbott said his focus was roads.