Fine Gael justice spokesman Alan Shatter has predicted the Government could “disintegrate” over the weekend.
Mr Shatter said the Government was now severely dysfunctional and in "total meltdown" and incapable of governing.
No-one should take it for granted that it will survive until the election day, planned for March 11th, he said.
Mr Shatter said the "shambles" of recent days in Leinster House had left many people despondent and disillusioned but it was now time to restore faith in politics.
He was speaking at the unveiling by Fine Gael of a third candidate in Dublin South, banking consultant Peter Mathews, on the plinth of Leinster House this morning. He will stand alongside Mr Shatter and Olivia Mitchell.
Mr Mathews, a chartered accountant by training, has been a prominent critic of the Government's strategy for dealing with the economic crisis over recent years. He claims to have accurately predicted the size of the property bubble and opposed the creation of the National Asset Management Agency to deal with the problem.
He will be attempting to win for Fine Gael the seat captured by RTÉ economic George Lee, which Mr Lee then gave up after eight months over differences with the party leadership.
Mr Mathews denied that he was a "celebrity economist" or "George Lee Mark II" candidate. He said comparisons with Mr Lee were irrelevant and his background as a banking analyst was "actually quite boring".
In accepting the nomination, Mr Mathews said he would do his utmost to return three seats for the party in this constituency. “The process of reconstruction, recapitalising and repairing the banking sector needs much more robust and transparent management than the limp performance of the current Government."
“It will take five years of dedicated hard work for a new government to lead us out of the mess. The first item on a Fine Gael government’s ‘to-do list’ will be renegotiation of the €85 billion Memorandum of Understanding with the IMF, EU and ECB and I look forward to playing my part in this process,” he said.
Mr Shatter said it wasn't Fine Gael's fault that Mr Lee had "walked away" and he rejected the "myth" that he had done so after being denied a policy input into the party.
Mr Mathews was educated at Gonzaga College in Dublin and UCD and joined ICC Bank in 1979. In 1999, he left to set up a consultancy specialising in property deals. He is married with four grown-up children and lives in Mount Merrion.
Last week, Senator Ross announced his decision to contest the election in the constituency as a non-party candidate after turning down an approach from Fine Gael.