THE National Roads Authority is preparing to sue the contractor who built the Dublin Port Tunnel following a series of system failures.
Engineers are taking apart the tunnel's Scada safety system "piece by piece" as part of a review of operations which is expected to result in legal action.
The NRA has told Nishimatsu-Mowlem-Irishenco, the joint venture which built the tunnel, that the system must be replaced and the contractor will be expected to pay.
If a dispute arises, the NRA has vowed to go to the courts.
The Scada safety system controls the detection of vehicles, fire suppression mechanisms, closed circuit television and emergency lighting and is described as the "eyes, ears, nose and throat" of the tunnel.
Its failure has led to the tunnel being closed more than 20 times since it opened in December 2006, resulting in traffic chaos in the capital.
Informed sources have told the Irish Independent that the taxpayer will not be paying for any replacement systems required in the €752m tunnel, which is Ireland's most expensive piece of infrastructure.
"There were quality assurances with the product, and we're saying to the contractor who built the tunnel that we're taking it apart and conducting a full review," one said.
"You will pay us to replace it, at your own cost. If it's a lightbulb that's broke, we look at the cost of replacing it. If it's €10, give us €10 or do it yourself.
"The Scada system is our eyes, ears, nose and throat. The manual override systems work fine, but we're taking it apart, the whole thing. There's a bond lodged for this, and these guys are insured."
"A big firm don't want residual wrangling. These people have reputations and don't want them dragged through the mud. We're going to seek all remedies open to us to ensure we get justification and that includes taking legal action."
The likely cost of replacing the system, which also controls communications, computer control systems, smoke detectors and power supply, could reach as much as €10m.
The likelihood of legal action arose after a Freedom of Information request seeking access to NRA records concerning the reliability of the tunnel's Scada system was refused.
The reason for refusal was that the documentation could be used in legal action against the joint venture.
The NRA said a review was underway.
"A detailed review of all operating systems in the tunnel will conclusively examine if there are any issues with the operating system," a spokesman said.
Dublin City Council, which commissioned the tunnel, is already in a dispute resolution process with the contractor over the final construction bill.
Legal action over the Scada system will be taken as a separate action. Last March it emerged the turbo-jet fans used to clean the air in the tunnel had to be replaced at a cost of €850,000, a year after being installed.
NRA sources have also said they were "not confident" about the reliability of the systems in place, but have stressed that the tunnel is safe.
Standard clauses in operation contracts can impose penalties against operators who fail to run the system as specified in the contract.
The tunnel is under warranty for 12 years, and for the first two years the builders are required to pay for any faults or failures. For 10 years after that, they must pay contractors employed by the NRA to carry out work on the faulty system.