Irish low-cost airline Ryanair will submit a complaint to the European Commission against Dublin Airport Authority (DAA) over its plans to build a second terminal, the carrier said on Tuesday.

Ryanair has long sought a second terminal at Dublin Airport, to be run by the airline or another independent operator rather than the DAA.

Europe's leading budget carrier says it wants to keep a lid on the cost of the development, which it says could drive up passenger charges by as much as 60 percent.

The airline, which reiterated an offer to build the second terminal at Dublin Airport, believes the state-run authority, which last year said it would build a second terminal for EUR170 million - EUR200 million euros (USD$216 million - USD$254 million), has abused its monopoly position.

Ryanair said the proposed cost of building Terminal 2 had rocketed to EUR750 million (USD$953 million), including the EUR150 million (USD$190 million) cost of writing off a pier in the DAA-run Terminal 1, but would not accommodate any more passengers than previously estimated.

"Ryanair... will submit a complaint to the European Commission against the DAA for abuse of its monopoly position at Dublin Airport, which has resulted in the T2 costs rising fourfold even before planning has been applied for," it said in a statement.

Responding to Ryanair's comments, the DAA said the increased cost was because of 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 EUR400 million (USD$509 million) cost of T2, at current prices."

But Ryanair CEO Michael O'Leary told reporters the airline would not use the terminal if built as currently planned.

"We wouldn't darken the door of this building," he said.

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 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".

O'Leary said he was doubtful of success with the Competition Authority in Ireland but was hopeful the complaint to the European Commission would succeed.

"I think our complaint to the European Commission will have a lot more success," he said.

He also said Ryanair would oppose any attempt by the DAA to impose a mooted 25 to 60 percent 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.