The cost of repairing faults on the Luas light rail line could cost millions of euro more to repair than original estimates.
A study commissioned by the Railway Procurement Agency (RPA) - the body responsible for the system - originally found deficiencies in the bonding material used beneath the city sections of both LUAS lines.
But the RPA has now received further reports that cracks are also beginning to appear in some of the concrete blocks which are used to support the track.
This could lead to excessive widening between rails if the problem is not corrected.
"There are some areas where there's a slight shrinkage problem between the concrete and the tray (which supports the track). It's not significant and it doesn't jeopardise the safety of the system," said an RPA spokesman.
The cost of the Luas repairs, which could run up to €10 million, are to be borne by the construction company responsible. The repairs are expected to begin within the coming months.
PA