Update - 8.10pm: Archbishop Eamon Martin has said it is with great sadness that he learned of Bishop Casey's death and has commended him for his work with Trócaire.
"It is with great sadness that I learned today of the death of Bishop Eamonn Casey. I wish to sincerely acknowledge the contribution of Bishop Casey to the work of the Irish Catholic Bishops’ Conference over twenty-three years during his time as Bishop of Kerry and as Bishop of Galway.
"Bishop Casey was a long-serving member of the standing committee of the Bishops’ Conference and, in 1973, was one of the founder members of its overseas development agency Trócaire. Bishop Casey’s inspirational leadership of Trócaire pioneered a very significant pastoral outreach from this country towards the most vulnerable people in the developing world, while at the same time he energetically raised awareness of overseas development issues at home in Ireland. Bishop Casey led Trócaire as its chairman until his resignation in 1992. Bishop Casey also contributed to the planning of the successful 1979 apostolic pilgrimage to Ireland of Pope Saint John Paul II. Both as priest and bishop, Bishop Casey’s ministry on behalf of Irish emigrants is well known and was of immense significance in particular to the Irish in Britain.
"At this sad time for Bishop Casey’s family, and for the dioceses of Kerry and Galway, I invite the faithful to pray for the repose of Bishop Casey’s soul. Ar dheis Dé go raibh a anam."
Update - 7.45pm: Trócaire has this evening issued a statement saying Bishop Casey's work with them in the 1970s and 1980s had benefited millions of people around the world.
Michael Kelly, editor of the Irish Catholic newspaper, said: "Eamonn Casey continued to be someone who fascinated people and I think the level of interest, even now in his passing, will be something remarkable.
"I think that is much more for what the revelations about Bishop Casey represented rather than anything personal about the man himself."
Update - 7.05pm: President Michael D Higgins has expressed his sadness at Bishop Casey's death.
He has praised his work as Chairman of Trócaire, and his role in campaigns for justice in the developing world.
Update - 6.35pm: The family of the late Bishop Eamonn Casey, including his son, have released a statement on his death saying he "was a great source of love and support".
They said: “On behalf of his son, Peter, his brother, Father Micheál, his sister, Ita Furlong, nieces and nephews, grand-nieces and grand-nephews, great-grand nieces and great-grand nephews, we wish to acknowledge the priestly work of Bishop Eamonn, especially in the pursuit of social justice for the marginalised, as evidenced by his work with Shelter in London in the 1950’s and 1960’s and later with his involvement in the setting up and development of Trócaire.
"Notwithstanding the demands on his time, Bishop Eamonn was a great source of love and support, making himself available to celebrate and to empathise with us in all our important family occasions.
“We wish to thank all of those who supported him in the past, in particular, the clergy and the people of the dioceses of Galway and Kerry, the Irish community in London, his many friends in Limerick and throughout the country and abroad. We would like to extend a very special and sincere thank you to the Sisters of Charity of the Incarnate Word, the management and staff of Carrigoran Nursing Home, Newmarket-On-Fergus, Co Clare, whose care for Bishop Eamonn was of the highest possible standard and ensured that his comfort, dignity and pastoral needs were provided for at all times.
“We respectfully ask that members of the media facilitate the privacy of the family during and after the funeral ceremonies.”
Funeral arrangements have not been finalised.
Update - 6pm: Father Diarmuid Hogan of the Diocese of Galway and Kilmacduagh confirmed the death of Bishop Eamonn Casey.
The statement said: "Having been ill for some time, Bishop Eamonn Casey, Bishop Emeritus of Galway and Kilmacduagh, died peacefully early this afternoon at Carrigoran Nursing Home, Co Clare.
"There are no further details available, including funeral arrangements, at the present time.
"Ar dheis Dé go raibh a anam uasal."
Bishop Casey had been in the nursing home for six years.
Earlier: Bishop Eamonn Casey has died, aged 89.
He is reported to have passed away peacefully at a nursing home in Newmarket-on-Fergus, Co Clare, this afternoon.
Mr Casey left Ireland amid controversy in the early 90's after it was discovered he had fathered a child with an American divorcee Annie Murphy.
Eamonn Casey was ordained a Catholic priest in 1951- he was appointed Bishop of Kerry 18 years later, and Bishop of Galway in 1976.
He was seen as a progressive and highly influential member of the Church, until his resignation in 1992 after reports surfaced of his sexual relationship with Annie Murphy - with whom he had a son.
It was a pivotal moment for the Church in Ireland, which until then held considerable influence over society and politics.
It is understood Mr Casey passed away this afternoon following a long illness.