The Fine Gael leader, Mr Michael Noonan, last night described Mr McCreevy's comments on the Nice referendum result as "reckless beyond belief". The Minister for Finance's remarks had undermined the Taoiseach's attempts to placate EU leaders in Gothenburg, he said. Mr McCreevy had made a "figure of fun" of Mr Ahern.
He added: "Mr McCreevy is known for his hubris and arrogance, and while his most outlandish statements may run well on the domestic stage, these statements turn the Minister, the Taoiseach and his Cabinet colleagues into figures of fun when expressed at an international forum."
In the wake of Mr McCreevy's comments, it was difficult to see how the Taoiseach could lay the groundwork for a second referendum on Nice, the Fine Gael leader said.
He called on the Taoiseach to "immediately deal" with his Minister of Finance and restore confidence in the Government.
"The Taoiseach must take a grip on affairs. For some months now he has shown no leadership across a range of issues, and his moral cowardice in failing to tackle ministers who are clearly out of line with Government policy is destroying the Government's authority to govern," he said.
The Labour leader, Mr Ruairi Quinn, described Mr McCreevy's comments as a "bizarre intervention" that would damage Ireland's standing in the EU. It also challenged the authority of the Taoiseach, he said.
"What are our colleagues in Europe to make of a Government whose leader `regrets' the outcome of the referendum on Nice, while his Minister for Finance describes it as `a healthy development' and boasts of his own role in creating a climate where a No vote was possible?" he said.
The Minister's remarks would give heart to an emerging Eurosceptic wing within Fianna Fail, Mr Quinn said.
"This is a dangerous development for this country. The Taoiseach must now re-assert his authority over his Government colleagues if we are to find a way forward which will both respect the concerns of the Irish people and make enlargement possible," he concluded.
The Green Party TD Mr Trevor Sargent accused Mr McCreevy of "speaking out of both sides of his mouth".
"He is doing what comes very naturally to any Fianna Fail minister. He is trying to see which way the wind is blowing and trying to blow with it."
The Minister was looking towards the next general election and was wary of alienating voters, Mr Sargent said. His remarks did not point to any shift in the Government's determination to push through the Nice Treaty. "It's asking an awful lot of people's tolerance that they give credence to these comments," he added.
Sinn Fein Dublin councillor Mr Sean Crowe said he was "amazed" at Mr McCreevy's comments. He accused the Minister of hypocrisy, claiming Mr McCreevy had attempted to stifle debate on the treaty in the run up to the referendum. "These comments are disgusting and show that Mr McCreevy has a brass neck second to none in the Government," Mr Crowe said.
"The Government has failed to recognise that the people voted No and are now trying to cobble together a solution. It's paddy whackery of the worst order. Mr McCreevy is trying to keep voters happy while the Taoiseach is apologising to EU leaders for their actions," Mr Crowe added.