Reaction:Labour leader Pat Rabbitte said this afternoon he believed Michael McDowell would "manufacture an excuse" to break up the Government.
Fine Gael leader Enda Kenny
Speaking after Tanaiste Mary Harney announced she was stepping down as leader of the Progressive Democrats, Mr Rabbitte described that party as "dysfunctional".
"I said at Mullingar on Tuesday that the PD bust up might sunder this government earlier than expected. I do not believe it is credible for the government to go on as if nothing has happened," Mr Rabbitte said in a statement. "The forcing out of Mary Harney leaves a dysfunctional minor partner in government.
"It is now likely that Michael McDowell will manufacture an excuse to break up the government and save the PDs. Increased crime, the hospital beds crisis and rising prices will all be lost in the new arrangement."
Fine Gael leader Enda Kenny paid tribute Ms Harney saying she was "a politician of integrity and honesty."
He said she had worked with "great dedication for her constituents and the country when in office.
"I have always regarded her as a conviction politician and throughout her political career she showed considerable courage on many occasions. I wish her and her husband Brian well with her decision. "The wider political implications of this decision will no doubt emerge over the coming days and weeks," Mr Kenny added.
Former Fianna Fáil minister and current EU Commissioner Charlie McCreevy, also paid tribute to his former Government colleague.
Mr McCreevy said Mary Harney had been "one of the outstanding politicians of her generation".
EU Commissioner Charlie McCreevy
"Since entering public life nearly thirty years ago she has been consistent, courageous and determined in advocating the distinctive economic and social policies in which she passionately believes. As an orator, advocate and influencer she has been second to none," he said.
He said that in ministerial office, she has had "tangible and lasting achievements in every area in which she has worked - the environment, enterprise, trade, employment, and more recently health".
"Her strong will and determined leadership have been the hallmarks of her tenure in office. She has never shirked from taking on vested interests, however powerful, when she considered them detrimental to the wider public interest."
Mr McCreevy said the outgoing PD leader had been "a formidable advocate of the liberal economic policies that we moulded and implemented together and which have delivered the sustained economic success that Ireland enjoys today".
"On some issues we differed and occasionally fought tough political battles in private. But throughout our thirty years in politics she has been consistently loyal and trustworthy and remains among my closest and most valued friends."