The Taoiseach has challenged Sinn Féin on allegations of corruption made by the party against other parties.
Mr Ahern was responding to remarks by the Fine Gael leader, Mr Enda Kenny, on alleged funding of Sinn Féin by illegal IRA activities.
Mr Ahern said: "If some members of Sinn Féin want to lay charges about corruption against other parties, they should consider very carefully where they are coming from on the whole issue.
"I have made that point outside, and I say the same again here."
He added that he could not share with the House the information he received in confidential briefings from the Minister for Justice, Mr McDowell, on security matters. "That has never been done in this House, and I am not going to do it. I have all the time made it clear that I believe that Sinn Féin and the IRA are two sides of the same coin."
He said any evidence of crime was a matter for the Garda.
Mr Kenny said the Minister for Justice had said there was an indivisible wall between Sinn Féin and the IRA, and that money available to one organisation was available to the other.
He asked if Mr Ahern had called in Mr McDowell and examined the evidence available, which left the Minister for Justice in no doubt that funding was being made available to Sinn Féin through senior IRA personnel involved in organised crime.
"If you have seen that evidence, Taoiseach, in your capacity as Taoiseach, and head of Government, and head of the EU, what do you propose to do about it?"
The Fine Gael leader suggested that Mr Ahern had a role in the matter in seeing that the laws of the State were upheld. The Minister for Justice was no fool, and he was speaking based on information from intelligence sources.
He said it was "astonishing" that Mr Ahern and the Government had not upheld their remit based on the categorical statement from Mr McDowell that organised crime and senior IRA personnel were involved in funding Sinn Féin.
Mr Ahern said he had no role in criminal investigations. "Obviously, whether it is in Northern Ireland or the Republic, we will do all we can to pursue the ending of any activities, including punishment beatings."
