The Pope "has honoured Dublin with a pastor of international reputation", the Taoiseach said at the weekend.
Welcoming the appointment of Dr Diarmuid Martin as Coadjutor Archbishop, he said he "has been a notable and respected voice in the international arena" in the pursuit of justice and peace.
"His evident concern for a just international order and for the needs of the poor and oppressed has lent authority to that voice. He will, therefore, bring to his new responsibilities a commitment to justice and a proven capacity for leadership."
Mr Ahern also said it was right at this time to recall the service of Cardinal Desmond Connell to the people of Dublin. "He has led the church in Dublin through a very difficult and testing time and he will, I am sure, welcome the appointment of the new coadjutor."
The Catholic primate, Dr Seán Brady, was "delighted at the news." He had known Dr Martin for more 20 years "and I consider him an excellent choice for the new and onerous appointment which he undertakes", he said.
The Church of Ireland Archbishop of Dublin, Dr John Neill, said Dr Martin brought to Dublin invaluable international knowledge and experience which, in the new scene in Ireland, would be of immense importance.
In this work "Archbishop Martin will have worked frequently within an ecumenical context and such experience will contribute much as we witness together to the Gospel in a secular society", Dr Neill said.
He also rejoiced for the Cardinal that he would have this support in his ministry and he thanked Cardinal Connell "for the friendship and welcome he afforded to me on my appointment to this diocese last autumn".
Father Martin Cosgrove, chairman of the Dublin Council of Priests, extended "sincerest congratulations" to Dr Martin and assured him of "the warmest of welcomes".
"Cardinal Connell has looked forward to this day for a long time" and he paid tribute to the Cardinal for his "sincere determination, not always appreciated or understood, to provide positive leadership for the diocese".
Ms Marie Collins, who along with Mr Ken O'Reilly has been assisting the archdiocese in dealing with clerical child sex abuse, welcomed the appointment as "very hopeful". She emphasised the need for issues to be really addressed, not just in terms of better presentation.
