Des O’Malley has been described as a “giant of politics” and mould-breaking leader who the State owes a “significant debt of gratitude”.
Mr O'Malley, the founder of the Progressive Democrats and former Fianna Fáil minister, died aged 82. He had been unwell for some time.
President Michael D Higgins led tributes to Mr O’Malley. He said he news of the death of Mr O’Malley “will have been received with great sadness by all” across the political spectrum.
“His contribution to public life as founder and leader of a political party, as cabinet minister and as Dáil deputy, was extensive and meaningful.”
Mr Higgins added: "His deep commitment to serving the people of Limerick, to the Republic, and to the parliamentary process, since he was first elected to the Dáil in 1968 stands as an outstanding example of dedicated public service, often delivered under great pressure."
He said Mr O’Malley had “a major influence on Irish politics, and his legacy and integrity includes a major contribution to the role of coalitions in Irish government formation”.
He said: “Those of us who had the privilege of working with him in the Oireachtas will also remember him as courteous, courageous and principled.
“As a friend he was gifted with a wry sense of humour, which he shared with generosity and a gift for irony.
“Sabina and I send our sincere condolences to his family, former colleagues and friends.”
Taoiseach Micheál Martin said he was “deeply saddened” to hear of his death.
“His was a life of courage and consequence,” he said.
“He loved his country and was fearless in challenging those who used violence to undermine it.”
Mr O’Malley would be remembered at the Government’s meeting on Wednesday, the Fianna Fáil leader said.
Speaking after a Cabinet meeting on Wednesday, Mr Martin said Mr O'Malley "truly was a mould-breaker".
Tánaiste and Fine Gael leader Leo Varadkar said Mr O'Malley "was a giant of politics."
“He broke the mould of Irish politics and left a lasting and positive legacy,” he said.
Former Progressive Democrats leader, Fine Gael TD Ciarán Cannon, said Mr O’Malley “never saw politics as a means to enrichment, but rather a way to serve his country and its people, working in their interests throughout his life.”
Geraldine Kennedy, former Progressive Democrats TD and ex-editor of The Irish Times, said it would be “extremely difficult , if not impossible” for the latest generation of voters to realise what an important contribution Mr O’Malley made to Irish political life.
“All of his actions, in retrospect over the years, were dictated by the democratic good of the people,” she said.
Mr O'Malley would have made "a great Fianna Fail leader if he had been allowed to run instead of George Colley opposite Charles Haughey in 1980," she added.
“He changed politics when he was convinced to enter Government with Fianna Fail in 1987.”
John Higgins, general secretary of the Progressive Democrats for 10 years and the party’s national director of elections, said Mr O’Malley was “opinionated and controversial but he epitomised great courage.”
“Any young person going into politics today, if they just stand by his principles, it would make for a great country going forward,” he said.
In the North, SDLP leader and Foyle MP Colum Eastwood said Mr O'Malley was "a true statesman", while Alliance party North Down MP Stephen Farry said he "was a hugely influential figure in Irish politics and a good friend to the Alliance party".
Minister for Justice Heather Humphreys offered her condolences to Mr O'Malley's family, friends and former colleagues.
She said: “Aged just 31, Des O’Malley was appointed Minister for Justice at one of the most difficult and threatening times in the State’s history.
“Des, his late wife Pat and their family endured great risk including threats from those who sought to undermine the authority of this State but Des never wavered in his duty and commitment to preserving our State and the safety and security of all its people.
“He was a republican in the truest sense of the word, one who broke the mould of Irish politics and helped modernise our society and our economy.”
Willie O’Dea, also a former Fianna Fáil minister and long-time TD for Limerick, said Mr O’Malley was “straight as an arrow with no hint of corruption ever”.
On Mr O'Malley's challenges to former Fianna Fáil leader Charlie Haughey, which saw him expelled from the party in 1984, Mr O'Dea said "even those on the opposing side to Des would concede that he had a powerful intellect."
“Des was deeply involved in a number of attempts to unseat Haughey as leader of Fianna Fáil and I supported him on each and every occasion,” he said.
“Had he succeeded, the history of Fianna Fáil might have been very different and I have no doubt that we’d be in a much better place than we are now.”
Mr O’Dea added: “I think the State owes him a significant debt of gratitude.”
Mr O'Malley was elected as a TD for Limerick in 1968 and was appointed Minister for Justice during the Arms Crisis of 1970.
A fierce opponent of Charles Haughey, he was expelled from Fianna Fáil in 1984 by Haughey and went on to found the Progressive Democrats in 1985, becoming its first leader.
He led the PDs into a coalition government with the Haughey-led Fianna Fáil in 1989, becoming Minister for Industry and Commerce and reaching an uneasy rapprochement in with Haughey in Government.
He stepped down as leader of the PDs in 1993, but remained a TD for Limerick East until his retirement from active politics in 2002.
His wife, Pat, predeceased him in 2017. The couple had six children.
The Taoiseach, Mr Martin said Mr O'Malley was a "major figure in Irish public affairs" for more than 30 years "with determination and a commitment to making Ireland a better place."
As Minister for Justice he “dedicated himself to facing down an illegitimate campaign of violence that directly targeted the institutions of the State,” he said.
As Minister for Industry and Commerce he was instrumental in “attracting critical investment in our country and helped to develop new industries.”
Mr O’Malley was already a “political colossus” before founding the Progressive Democrats and took a “huge gamble” in setting up the party, former Government press secretary and party director of policy Stephen O’Byrnes said.
“Des was a man of extraordinary courage and conviction,” he said.
“The fact that he took the lonely road of setting up the new party, after already being thrown out of Fianna Fáil – he was a man who didn’t settle for a comfortable position in politics.”
Mr O’Byrnes also remembers his former party leader as a “tough man to work for.”
“He didn’t suffer fools. He had a very short fuse,” he said.
“But an outstanding feature of him was you could have a very strong argument – or a row – with Des on policy matters, then afterwards it would be a case of going to Buswells Hotel and having a drink.”
Mr O’Byrnes, who served as Government press secretary from 1989 to 1992, said Mr O’Malley’s political courage and his commitment to politics “took a big toll on his family life”.
“Going back particularly to the period when he was Minister for Justice for Fianna Fáil, he was under armed protection by the Special Branch because of the IRA campaign.”
Mr O’Malley’s wife, Pat McAleer, was from Omagh in Co Tyrone, and her family had businesses blown up by the IRA twice in the 1970s, he said.
“Notwithstanding the difficulties of that nature, when his life would have been under threat, he did the right thing, he was fearless.
“Des didn’t look at the odds on things, if he believed it was the right thing, then he pursued it, whether 100 people were with him or he was on his own, he just ploughed ahead.”
Paul Mackay, who helped found the PDs, said he was a man of integrity but was “difficult to deal with on a personal level”.
“He was very tetchy at times,” he said.
“We all have our foibles and difficulties, and the closer you got to him the more difficult he was. Outwardly, he was very charming, very popular and successful but if he was in bad humour he was difficult.
”That was the negative but the positive was he was a good man and full of integrity.
“When he became Minister for Justice, he really showed his mettle there. He was being hounded by the bloody Provos at that time. He had a very difficult family life, moving from house to house, moving his family.
“But he still carried out his functions – he protected the State.”