The Taoiseach repeated his assertion that a ban on corporate donations to political parties could be unconstitutional.

Mr Ahern came under intense pressure from Fine Gael and Labour to support their ban on these donations. He said that for "constitutional and legal reasons" the issue was not simple and should be considered by an all-party Oireachtas committee.

"I have cited what the Honourable Mr Justice Brian McCracken said in the conclusion of his findings in his tribunal report. He said the tribunal did not consider it practical to prohibit all political contributions and rely solely on public funding of political parties. Indeed to do so might give rise to serious constitutional difficulties."

Earlier, the Labour leader, Mr Ruairi Quinn, urged Mr Ahern to accept a motion on the Order Paper that would end "for ever the corrupting of the political process in this country by the extension of the continued funding of political parties by corporate donations.

"Has the Taoiseach learned anything from the tribunals relating to this matter? Does the Tanaiste still go along with corporate donations?"

Mr Ahern asked why Mr Quinn had refused last Easter to join with other parties in examining funding issues so that all of them could be dealt with. "At the time Fine Gael was prepared to do so, as were other Opposition parties."

He added that at the time he said the Government was going ahead with the public office commission legislation and the Electoral Act, and that there were issues to be dealt with.

"When he mentions the pollution of corporate donations, as if every business person in this country was corrupt, he never goes on to explain what exactly corporate funding is.

"Does it incorporate companies, partnerships or wealthy individuals who could spend £20,000 or £30,000 out of their back pockets? I do not know any of those."

Amid uproar from the Opposition benches, Mr Ahern said: "Well, they are not close to me."

Mr Alan Shatter (FG, Dublin South) remarked: "How is it that Ray Burke and Deputy Lawlor knew them?"

Mr Ahern again urged all-party consideration of the issue, adding: "If we are really worried about people being corrupted, both the Tanaiste and I are ready and willing to deal with these issues, but we need other people to do so. We will not succeed in doing it by giving one-liners on the Order of Business.

"The way to do it is by way of an all-party committee. Again, I take the opportunity to say to Deputy Quinn that I am prepared to address the issues raised by the Honourable Mr Justice Brian McCracken and the other advice given to me by the Attorney General, which he gave to Deputy Quinn the day of the meeting in my ante-room, and to try to deal with this issue. I am ready to do that at any time."

Mr Quinn said Mr Ahern should publish the legal advice. "We believe it is not unconstitutional."

The Fine Gael leader, Mr Michael Noonan, asked if Mr Ahern had inquired of Ms Harney if her party had moved position on the issue.

He added that Mr Ahern seemed to misunderstand the issue: the public could no longer distinguish between clean money and dirty money and it was the perception rather than the reality that the Taoiseach must change if he was going to renew politics.

"In the first instance, it is the Taoiseach's job to restore democracy and renew politics. We are showing the Taoiseach how to do it and we are going to carry this case forward. It is a very serious issue."

Mr Ahern said: "I am not too sure if it is just clean money and dirty money. The deputy also seems to have a problem about hidden money and people do not know who paid it."

Mr Noonan said: "The Taoiseach has slurred me personally and my party and I would like him to correct the record."

Mr Ahern replied: "I know the cost of doing a large poll. If Deputy Noonan would tell the House who paid for the (FG leadership) poll, then I will withdraw it."