He also served on the Independent Commission for the Location of Victim's Remains
Tributes have been paid to Frank Murray, former secretary-general to the government.
He died suddenly over the weekend.
Over his career, Mr Murray served at the Land Commission, the Houses of the Oireachtas and at the Department of the Taoiseach.
He also served as private secretary to then-Taoiseach Liam Cosgrave.
On retiring he assumed a number of roles - including as Commissioner on the Independent Commission for the Location of Victim's Remains, in which he was currently serving.
Paying tribute, Justice Minister Charlie Flanagan said: "He had a particular commitment to the cause of the disappeared and their families and he never wavered in his pursuit of the humanitarian objectives of the commission.
"On Palm Sunday of this year, as every year, he attended the mass in St Patrick’s Cathedral Armagh for the Disappeared to stand with the families and to show his unstinting support for the return of their loved ones."
President Michael D Higgins said: "As a public servant, in a distinguished career, he held the respect of members of the government right across the political spectrum.
"I have the warmest memories of his service in the 1990s.
"After his retirement, to his native Leitrim - for he was a proud Leitrim man - he went on to serve the State in a most valuable way, including in the search of the Disappeared.
"To his family and friends, I offer my deepest condolences."
The Taoiseach Leo Varadkar said he learned of Mr Murray's death "with sadness".
He said: "Frank Murray was an exceptional public servant.
"He enjoyed a long and distinguished career in the civil service and I want to acknowledge his many years of loyal service to many governments.
"In particular, I also want to acknowledge the professionalism and sensitivity he brought to his work over the past number of years at the Independent Commission.
"He was also a proud Leitrim man who never forgot his roots".