Consultants managing the competition to operate the Luas light rail system in Dublin have shortlisted five groups for the contract.

The group of 12 original bidders is believed to have included Iarnrod Eireann and Dublin Bus, but the CIE companies were not shortlisted.

A Department of Public Enterprise spokesman said successful first-phase bidders were informed last week.

He declined to reveal the unsuccessful bidders. Only one Irish firm is included among those selected for the second phase of the competition.

A bid by Aircoach, a Dublin bus firm, was submitted in partnership with the British firm National Express.

Other British group short listed were the rail operator Connex, bus firm Stagecoach, and facilities management group Seroc. Transdev, a French-owned group, was also shortlisted.

It is thought a preferred bidder will be chosen this summer. That group will operate the Luas services to Connolly Station from Tallaght and to St Stephen's Green from Sandyford.