Fianna Fáil is promising to examine the possibility of introducing LUAS-style tram services in Cork, Galway, Waterford and Limerick if it is re-elected to Government this year.
The promise is contained in the party's transport manifesto, which was launched in Dublin today.
Most of the document is a repeat of projects already announced as part of the current Government's Transport 21 plan.
Opposition parties have criticised the announcement, calling it an election stunt.
Meanwhile, Miniser for Transport Martin Cullen used today's launch to announce that the planned metro line serving Dublin Airport would go underground through Ballymun following local objections to an overground line.