A special Requiem Mass has been celebrated for Pope John Paul II at Saint Peter's Cathedral in west Belfast.
Dr Patrick Walsh conducted a Requiem Mass for the Pope
During his homily, Bishop of Down and Connor Dr Patrick Walsh recalled his past meetings with the Pope.
Dr Walsh said the pontiff had always expressed a particular interest in Northern Ireland and the Troubles.
"Each time he inquired, with much concern, about Northern Ireland and in particular about Belfast," he said.
"He was anxious during our dreadful years of violence to ask about and to express his concern for the people of Belfast and, in a special way, to ask about the ministry of the priests in conditions of stress."
A Mass of remembrance was also held in Dublin's pro-cathedral.
Irish President Mary McAleese and Taoiseach Bertie Ahern were among those who attended.
Meanwhile, the head of the Catholic Church in Ireland has called for Pope John Paul II to be declared a saint.
Archbishop of Armagh Sean Brady made the comments on Tuesday after a special Mass in St Patrick's Cathedral in Armagh.
Archbishop Sean Brady said the Pope set an inspiring example
The congregation included Cardinal Cahal Daly, the Church of Ireland Archbishop, Robin Eames, and Secretary of State Paul Murphy.
Dr Brady said canonisation would help the Pope's work to continue and mean he would be venerated by the church.
"My hope is that he would be canonised," he said.
"If it would serve to people to take on board and live out the kind of things that he believed in, and taught and stood for, I think that would be important.
"The man gave endlessly of his time and energy and people energised him and he liked them. It certainly has revolutionised the role of the papacy."
Books of condolence are being signed across Northern Ireland to allow people to write their own personal messages of respect for the Pope, who died on Saturday, aged 84.
Northern Ireland Secretary Paul Murphy added his signature to a Book of Condolence in Armagh, where he personally expressed his sorrow to Dr Brady.
"We reflect on his death as a great loss not only for the Catholic Church but also for humanity as a whole," he said.
"All of us who mourn also feel an overwhelming sense of gratitude to God for sending us a man whose courage and faith was an inspiration to everyone and especially to those facing suffering or persecution."
Messages of sympathy have been issued by religious and political leaders from all communities.
The body which oversees Catholic schools in Northern Ireland has also said Catholic schools can close on Friday for the funeral if they wish.
The Catholic Council for Maintained Schools said the final decision on whether individual schools closed was up to boards of governors.
Jim Clarke from the CCMS said they were giving schools flexibility.
"If schools wish to close, they have at their discretion a number of optional holidays - one of which they can use for this purpose," he said.
"Any school which has already used its allocation this year has the authority of the Department of Education to borrow, if you like, a day from next year's allocation."
Meanwhile, Irish Premier Bertie Ahern has been criticised for not holding a national day of mourning for the Pope, who visited Ireland in 1979.
Mr Ahern said schools would be allowed to close for the funeral if they wanted to and arrangements could be made for employees who want to attend Masses.
But the singer and former MEP Rosemary Scallon, better known as Dana, said an incredible number of people wanted a national day of mourning.
Pope John Paul II made Ireland the third pilgrimage of his 26-year pontificate when he visited for three days, a year after becoming pontiff.
He made an impassioned plea for peace in Northern Ireland, however, he did not visit the province.