There is "serious speculation that some damning evidence against the Taoiseach will be presented at future stages of the Flood tribunal," the Fine Gael leader told the Dáil during the debate about the appointment of a new chairman and members of the planning inquiry.
Mr Enda Kenny said, however, that he had "no evidence to substantiate that" other than hearing rumours.
He also warned that the public "would simply not wear" a situation where the Irish taxpayer "is going to have to fork out for the costs of those who have been deemed to have deliberately obstructed the workings" of the tribunal and its investigations "whether those costs be €10,000 or €10 million".
His view was backed by the Green Party, whose spokesman, Mr John Gormley said the very idea of the public paying the former minister, Mr Ray Burke €10 million "would defeat almost entirely the purpose of the tribunals" not only to establish what wrongdoing took place, "but also to ensure that wrongdoers are punished in some shape or form".
The Labour Party leader, Mr Pat Rabbitte, called for powers of tribunals to be extended so that costs could be reduced where lawyers engaged in "time wasting" and "red herrings" and he criticised the Government, who appeared to have "abandoned" the option of investigation by an Oireachtas committee, such as in the successful DIRT inquiry.
He hit out at the Minister for Justice, Mr McDowell, whose "principal contribution was to negotiate an €800 per diem increase for tribunal lawyers". Speaking during the two-hour debate on the inquiry that will now be called the Mahon tribunal, Mr Kenny paid tribute to Mr Justice Flood.
He had "set the standard" for other tribunals.
Referring to rumours of evidence against the Taoiseach he said that "if you're to believe some of the comments, this is evidence that as Deputy Rabbitte said some years ago, would rock not just the party but the country to its foundations".
The people of Ireland, who had "paid millions" for the first five years of the tribunal, were entitled to hear it.
It was their "democratic right" to hear the evidence, including the Gilmartin and Quarryvale modules.
However, the Taoiseach assured him that all the current modules would have to be heard in public.
Mr Ahern, who sat in the Dáil for most of the debate although he did not make a formal contribution, intervened while Mr Kenny was speaking, to clarify the issue.
Mr Ahern said the present modules would be heard by the Mahon tribunal.
The modules before the tribunal at present - "that collective group has to be investigated by the tribunal".
The Taoiseach added that "they have not decided what to do "with all the other modules".
