The Taoiseach, Mr Ahern, has rejected suggestions from unions at Aer Rianta that he did not adequately consult with workers on the planned break-up of the company.
"It's now over a year ago since the break up of the three companies of Aer Riant were announced by the Government," Mr Ahern said.
"The Minister has outlined that he is going to have another year of consultation, so that's two years of consultation. So I hope two years is enough for the trade unions," he added.
As unions plan to meet on the issue on Monday, the Minister for Tourism said any strike action at the Government's plans would be "inexcusable".
"Any such disruption would be inexcusable given the challenges and difficulties facing the tourism sector over recent years," Mr O'Donoghue said.
He said any disruption would "needlessly place many vulnerable jobs at even greater risk".
It is feared that passengers will face severe delays at airports in Dublin, Cork and Shannon next Monday, following an angry reaction from trade unions representing staff in the three main airports to establish Dublin, Shannon and Cork Airports as independent entities.
Up to 80,000 passengers use Dublin Airport daily at this time of year; a further 9,000 use Shannon and 8,000 use Cork.
Speaking on RTÉ's Morning Ireland today, The Minister for Transport, Mr Brennan, appealed to the unions not to disrupt traffic at the airport with any industrial action. He denied that privatisation was being considered.
"The last thing this country needs is disruption," he said, adding he was available to talk to unions at the airport "round the clock, if they want".
He insisted there was "no threat of job losses" arising out of the break-up plan. He claimed the three new airport authorities would offer passengers more choice and competition.
He said he was "absolutely convinced" that Cork and Shannon would be economic successes and would "blossom" in the years ahead.
Labour's Transport spokeswoman, Ms Róisín Shortall, criticised the decision, however, saying she preferred the introduction of autonomous boards within the company.
She said the Government move was an experiment, adding there was no reason to believe that Cork and Shannon airports could survive as independent entities.
But the Chambers of Commerce of Ireland (CCI) today welcomed the move and condemned SIPTU's threat of industrial action.
CCI chief executive Mr John Dunne said: "SIPTU's knee-jerk reaction to the Minister's announcement misses the core point. Experience has shown time and again that competition increases jobs and economic strength.
"SIPTU needs to grow up and realise that this move has the potential to be a fantastic opportunity rather than a threat if the unions respond constructively. Objection to change reasons of self-interest is not acceptable," he said.
Last night the vice-president of SIPTU, Mr Jack O'Connor, accused Mr Brennan, of "institutionalised vandalism". He claimed the plans were reckless and defied commercial logic.
Aer Rianta is seeking clarity from the unions about their plans.