Taoiseach Enda Kenny has extended his best wishes to Pope Benedict XVI after his announcement that he will shortly retire.
In a statement, the Taoiseach said the "momentous decision" was clearly one the pontiff had taken after careful consideration.
Meanwhile, Tánaiste Eamon Gilmore said he had heard of the pope’s decision to resign during a meeting today with Northern Secretary Theresa Villiers. He wished him well in his retirement, as did Ms Villiers. Archbishop of Dublin Diarmuid Martin said the announcement had come as a surprise although there had been indications that the pope's health had been diminishing.
In the Taoiseach's statement, he said: "On behalf of the Government and people of Ireland, I would like to extend best wishes to His Holiness Pope Benedict XVI following his declaration today that he intends to step down from his office."This is clearly a decision which the Holy Father has taken following careful consideration and deep prayer and reflection. It reflects his profound sense of duty to the Church, and also his deep appreciation of the unique pressures of spiritual leadership in the modern world. This is a historic day in the life of the Catholic Church and for the many millions of Catholics, both here in Ireland and around the world.
"Pope Benedict has given strong leadership and great service to the Church and her people for many decades. I know that all of their thoughts and prayers will be with the holy father at this time, and also with those who will shortly gather in conclave to choose his successor."
The Tánaiste said: "Like many in Ireland and Catholics in general, my concern is for the pope's health. I wish him well in his retirement. He is someone who has worked tirelessly as head of the Catholic Church.
"He has visited many areas of the world and worked for world peace. This was always at top of his agenda. We share that as a country - the desire to being peace to an world that is very troubled."
Dr Martin said it was "amazing" that the pope had continued with a full schedule until now.
“It's very clear that over the last months or so his physical health was declining and he had said on a number of occasions that if he felt that his physical and spiritual and mental health were a problem to him carrying out his duties, he would consider resigning.”
Dr Martin said people had tended to categorise Benedict "in one way or another".
"He was an extraordinarily rounded and a very different sort of man with many different aspects to his personality," he said.
The archbishop recalled meeting the pope during an Ad Limina visit to Rome. "I went out there with all my statistics ready telling him what was happening in Dublin."
And the pope had said: “I want you to tell me where are the points of contact between the Catholic Church in Ireland and those places where the future of Irish culture is being formed," Dr Martin recalled.
"He talked about the media, the universities, the Arts, about young people. It was the sort of question, actually, that the church in Ireland should be consistently asking itself and he was very sensitive to that. It was a long discussion – it was scheduled for 15 minutes and went on for 35. That was quite typical of the man."
The pope was also very interested in Ireland. Both Cardinal [Sean] Brady and I met him on a number of occasions about the sex abuse scandals and the attitude of the Vatican changed significantly under his pontificate. He took a much stronger line in addressing these issues."
Ms Villiers also wished the pope well in his retirement. “Relations between the Vatican and London have been very strong,” she said “They are their best in a long time. Pope Benedict was very well received during his recent historic visit to Britain.
"I wish him well in relation to his health and I wish the church well regarding his replacement."
Fianna Fáil leader Micheál Martin also extended his best wishes to the pontiff.
"I was extremely surprised to hear of the pope's decision to resign this morning and I know it will come as a great shock to many Catholics in Ireland and across the world. This must have been a very difficult decision for Pope Benedict and one that took a great deal of courage, and must be respected," he said.
"When Cardinal Ratzinger succeeded Pope John Paul II in 2005 there was much goodwill for the new pope in Ireland and I know that many people across the country will be equally welcoming for Pope Benedict’s successor in the weeks ahead.
"The principal concern of most people in hearing this news today will be for Pope Benedict's health. I want to extend my very best wishes to him as he focuses on his health and a new chapter in his life. I know the thoughts and prayers of many Irish people are with Pope Benedict at this time."
Richard Clarke, Church of Ireland Archbishop of Armagh and Primate of All Ireland, praised the dedication, humility and service that Pope Benedict displayed throughout his ministry.
"A scholar of great intelligence and learning, he was also a deeply self-effacing and spiritual human being. His clear devotion to the Lordship of Jesus Christ shines out in his prolific literary heritage to us," he said.
Northern Ireland Deputy First Minister Martin McGuinness said the pope's dramatic decision shows the extent to which health concerns were weighing on his mind. "I hope that the lifting of the onerous weight of the responsibilities of such an important world leader will ease the burden on him in his retirement," he said. "I wish Pope Benedict well, and like Catholics everywhere look forward to the election of the new pope at a time when the Church is at a crossroads."
SDLP leader Alasdair McDonnell MP said Catholics should be proud of a leader who has put his love for the Church over personal considerations.