Taoiseach Enda Kenny has extended sympathy to the family of Leitrim man Dermot Gallagher.
He stated "I am deeply sad, as is the Government, to learn that Dermot Gallagher has died.
"Dermot Gallagher was a patriot, an outstanding public servant who embodied the best of Ireland and its people. Dermot was an intellectually-brilliant yet unassuming man. He had a rare elegance and warmth. At every stage of his career, he used his contacts and authority to do good. He showed immense humanity and compassion to those who needed it most.
"A proud Irishman, he was the quintessential family man and Leitrim man. The waters of Leitrim flowed in his veins. Dermot used to say “a shroud has no pockets”. But there is neither shroud nor pocket big enough to hold even a minuscule amount of his wisdom, decency and kindness.
"Dermot Gallagher is a major loss to Irish public life. Today, Ireland is the less for his passing. I send my thoughts to his family, his friends and colleagues at this sad time.
"Dermot, ár gceol thú."
Meanwhile the Tánaiste and Minister for Justice and Equality, Frances Fitzgerald, T.D., also expressed her sadness at the passing of Mr Dermot Gallagher.
The Tánaiste said: "While Dermot will be remembered primarily for his invaluable contribution to the cause of peace on this island, on his retirement as Secretary General of the Department of Foreign Affairs he continued his very distinguished career of public service by serving for a number of years as Chairperson of the Garda Síochána Ombudsman Commission. He combined a deep respect for An Garda Síochána with a determination that all who served in it should live up to its highest standards.
"Dermot worked very closely with the Department of Justice and Equality during the peace process and he will be remembered with great fondness as a deeply cherished and trusted colleague.
"I hope that at this difficult time for his family and friends they will be able to take some comfort from the high esteem in which he was so widely held and the great progress facilitated by his untiring commitment to bring peace to the people on this island."