The death has taken place of Pat Magner, a former senator and member of the Labour Party for more than 50 years.
Mr Magner, who served in various roles in the party up until 2006, died on Monday.
Labour Party leader Ivana Bacik said he would be missed greatly and remembered with "immense affection and appreciation for his enormous contribution to public life as a senator and political activist, as well as for his long-standing and substantial commitment to the Labour Party".
He first joined the party in 1959, served as its national organiser and was said to have played a key role in many elections.
Ms Bacik said: "He served three times as a senator, and was involved in the Administrative Council and many other internal committees where he always worked for the best interests of our party.
"Pat was a loyal and trusted servant to the Labour Party over many decades, and a great friend and confidant to many.
"He will be remembered as a close ally of former party leader Dick Spring and for the immense work he did to build the party into an electoral force.
"Pat was not just held in high regard within the Labour Party but also by politicians from across the political spectrum."
Ms Bacik sent her sympathies to his wife Anne, their children, family and friends.
