The Minister for Transport, Mr Brennan, has hit back at the Ryanair chief executive's harsh criticism of the Taoiseach for delaying a decision on a second terminal at Dublin airport.

Mr Brennan said he expected to have a full Cabinet decision to proceed with developing the terminal before Christmas and hoped to see the project begin next year. He said it was unrealistic for Mr Michael O'Leary to expect the Government to move as rapidly as the private sector on such matters.

"He is not being fair when he equates the prime minister, as he calls him, to the chief executive of a multinational organisation. It is unfair to the Taoiseach to be attacking him in that way because he is waiting for proposals from me. I am making a judgment on how many battles I can fight on the one day. I want to get the break-up of Aer Rianta bedded down," he told The Irish Times.

"I will be recommending strongly to the Government that we put a second terminal in Dublin. The private sector has shown it is prepared to do it. This State is not so rich that it can turn down an offer from the private sector to supply us with a major new terminal at no cost to the State. The taxpayer gets this free so we would be mad to say no," the Minister said yesterday.

Mr O'Leary had said the Taoiseach, Mr Ahern, was "ineffectual" and "spineless", and called on him to start showing some leadership instead of "moping around and hoping that it will all work out in the end".

"I can understand his frustration but Michael also knows that the public sector does not move as fast as the private sector. It can't. We are operating in two different systems. I pulled back for a couple of months recently in order to get the break-up of Aer Rianta bedded down," the Minister said.

The Government has received 13 expressions of interest to develop the second terminal at the airport but the project is being bitterly opposed by Aer Rianta and the trade unions representing staff at the airport. In recent weeks, Mr David Begg, the general secretary of the Irish Congress of Trade Unions, met the Minister and the Taoiseach to stress deep reservations about changes at the airport.

Mr Brennan said he would continue to discuss these issues with the trade unions but said he was determined to move the second terminal project along swiftly. "The battle for the second terminal will be fought in the coming weeks."

Once it has been approved by the Cabinet, the Minister intends to appoint an expert committee, and may even reconvene the group headed by former civil servant Mr Paddy Mullarkey, which assessed the 13 expressions of interest for the Government, to select the winner.

"The transparency of that process will be critical. Every meeting, every bit of paper will have to be on the table. The public will have to be absolutely assured that it will all be done absolutely by the book," he said.

"I would love to see them on site next year."