Dublin City Council is continuing to play down leaks in the Dublin Port Tunnel despite new video footage showing widespread flooding along a 50-metre stretch of the facility.
News of the leaks first emerged last month, but the council insisted at the time that they would be repaired within weeks.
The new footage shows that this has not taken place and that widespread work will be needed to rectify the problem.
However, Michael Philips, a chief engineer on the project, said today that the situation was not serious.
"It's only a small leak," he said. "It's of no relevance to the programme. It's not causing any delays and as a result, we have not been pressurising to get it repaired.
"We had to wait for the Italian sub-contractor to come back. He's now on site and the repairs are being carried out."