The road building company SIAC has launched a High Court challenge to the awarding of the contract for the western bypass of Dundalk.
SIAC has alleged that proper procurement procedures were not followed and a late change to the tendering requirements effectively put it at an unfair disadvantage.
The action in the High Court is being defended by the National Roads Authority (NRA).
Four years ago SIAC accepted almost €4 million from the NRA and Limerick County Council in settlement of an action after a calculating mistake in the tendering process organised by Limerick County Council resulted in a contract being awarded to another contractor.
The public-private partnership contract for the Dundalk bypass, which links the existing M1 motorway to the Border with Northern Ireland, is worth an initial €100 million in construction terms. As such, it is almost three times bigger than the Limerick contract, which was estimated at €38 million.
However, the eventual value of the Dundalk project over the 30-year toll-gathering and maintenance period could be more than €300 million.
The contract for the Dundalk bypass was awarded earlier this year to a consortium involving Irish road builders Ascon and National Toll Roads, along with the Spanish firm Dragados and the Dutch parent of Ascon HBG. The winning consortium is known as the Celtic Roads Group.
In its petition to the court, SIAC said proper EU procedures were not followed in awarding the Dundalk bypass, because they were "negotiated procedures", a type of tendering which is used, according to the company, only in emergency situations. It also alleges a key requirement to have firm support from bankers was "watered down" in the last week of the bidding process, a move that weakened its position.
The NRA has said it will be defending the case vigorously.
Mr Justice Kelly in the High Court recently reserved judgment on a preliminary issue, a claim by the NRA that SIAC is too late in bringing its challenge.
The judge said he hoped to rule on that matter in two weeks.
