The Taoiseach, Mr Ahern, has said he knew months ago that Limerick West TD, Mr Michael Collins, had difficulties with his tax affairs.
He also said Dublin North TD, Mr G.V. Wright, would not be asked to resign his Dáil seat.
Mr Wright knocked down and badly injured a nurse in Dublin, 12 days ago, while driving under the influence of alcohol.
Speaking to journalists yesterday, Mr Ahern said he had spoken to Mr Wright yesterday morning. "He rang me this morning to apologise for the controversy that he's created - to me and to the party, obviously to his family - and he informed me that he'd be sending a written apology to the party for tomorrow."
Asked whether he'd be "forcing" him to resign, the Taoiseach said: "No I won't. I think G.V. Wright will now face, as any individual would, without fear or favour, the full rigours of the law. He knows that he was totally wrong."
He said his sympathies and regret went to the nurse, Mrs Ann Butler (50), from North Strand, Dublin, who was knocked down by Mr Wright two weeks ago.
It was "wrong" and "irresponsible" of Mr Wright to have driven under the influence of alcohol. "He apologises for it and he'll have to face the full rigours of the law," said Mr Ahern.
Turning to the controversy surrounding Mr Collins, who faces investigation by the Standards in Public Office Commission, following the disclosure that he had used an offshore account to evade taxes, Mr Ahern said he had known for "some months" that Mr Collins "was in communications with Revenue on a matter that would be coming forward in a Revenue report".
He said, however, he had not known the details of the situation. "He did not make aware the details of that [his problems with the Revenue Commissioners] then or since then. But he has, I understand from the chairman of the party, agreed to make the full facts available.
"He states that he was not in breach of the [1938 Statutory Declarations] Act but we have to wait to do that, because our rules are quite clear. Any kind of wrongdoing in the tax area - most of these are areas where I brought in the laws myself in the early '90s. And he'll have to explain that, not only to the Public Office Commission . . . the party will seek to do the same through our own ethics committee."
Asked whether Mr Collins, if he were found to be in breach of the Act or the spirit of it, should resign his seat, Mr Ahern said the Public Office Commission should be allowed to carry out its investigation before a decision on penalties should be made.
"Let's not try to get to the end of the process before it starts."
Betraying frustration with the problems caused for him by some members of his parliamentary party, Mr Ahern said he would not accept blame for driving a car under the influence of drink.
"And neither would I accept that I was in any way involved in any breach - if it is a breach - of Revenue laws.
"But, as always, as party leader, I'm left to sort it out."
