Ryanair is to complain to the European Commission about Dublin Airport Authority's (DAA) plans to build a second terminal.
The airline, which has long opposed plans for the DAA run both terminals, believes the semi-state company, which last year said it would build a second terminal for €170-200 million, has abused its monopoly position by allowing costs rocket, which would in turn drive up ticket prices.
It said the proposed cost of building Terminal 2 had ballooned to €750 million, including the €150 million cost of writing off a pier in the DAA-run Terminal 1, but would not accommodate any more passengers than previously estimated.
Earlier today Ryanair ceo Michael O'Leary said if his company built the facility it would save the DAA €610 million.
Mr O'Leary said: "The DAA cannot be trusted to build efficient, low-cost facilities. ... Having announced the second terminal in August 2005 at a cost of €170 million ... the DAA have now designed this facility, and the costs have exploded 12 months later to over €750 million."
"We wouldn't darken the door of this building," he added.
The carrier said it would oppose the proposed terminal at county council planning level. In addition, Ryanair plans to submit a complaint to competition authorities in Ireland calling for an investigation into the increase in estimated costs for the terminal.
The DAA said estimated costs had increased but only to €395 million at current prices. It attributed the increased cost to the "newly-emerging, aggressive plans of some of the key airlines" based at the airport.
"The DAA decided to accelerate its plans and build a 75,000 square metre terminal rather than the initially-planned 50,000 square metre facility," it said in a statement.
"This significant expansion in the scale of the development and the attendant increase in the complexity of some of its features represent the key reasons for the amended €400 million cost of T2, at current prices."
But Mr O'Leary told reporters the airline would not use the terminal if built as currently planned.
The carrier described the planned new terminal as "badly designed, in the wrong location" and "five times more expensive than other similar terminal facilities in the UK and Europe".
Mr O'Leary said he was doubtful of success with the Competition Authority but was hopeful the complaint to the European Commission would succeed.
He also said Ryanair would oppose any attempt by the DAA to impose a mooted 25 to 60 per cent increase in passenger charges.
In a bid to catch up with a surge in traffic since Ireland's economic boom in the late 1990s, the airport authority has embarked on a 10-year drive to raise capacity to 35 million passengers a year from the present 20 million.