The Taoiseach's representatives will, within 48 hours, press Ms Beverley Cooper-Flynn to resign from the Fianna Fail parliamentary party, whether or not she appeals the outcome of her libel case.
Mr Ahern's position of a fortnight ago - that she was entitled to "due process" in the courts before any political action against her - appears to have been abandoned amid overwhelming consensus within the party that she must go.
Mr Ahern moved publicly yesterday to narrow her options to those of resignation or expulsion. "We have an issue to deal with," Mr Ahern told RTE's This Week. "The party has rules and procedures . . . and these issues are going to have to be dealt with."
The Fianna Fail parliamentary party chairman, Dr Rory O'Hanlon, and the Chief Whip, Mr Seamus Brennan, agreed the approach with the Taoiseach on Friday. They will now seek to meet the Mayo TD before Wednesday's weekly meeting of deputies, senators and MEPs to outline the bleak scenario facing her.
They will tell her of the belief widespread in the party that she should go in the wake of her failed libel action against RTE and the award of all costs against her.
Ms Cooper-Flynn returned to Ireland at the weekend after a short holiday abroad with her father, former European Commissioner Mr Padraig Flynn. She could not be contacted for comment yesterday and her intentions could not be ascertained.
Mr Ahern's criticism of Ms Cooper-Flynn's behaviour yesterday was more strongly worded and unambiguous than anything he has said in relation to the other Fianna Fail deputies who have found themselves in trouble on ethical issues under his leadership.
"Tax evasion is wrong," he said. "Encouraging others to engage in tax evasion is equally wrong and everybody, I think, is aware of that. We take a very dim view of this particular case, and we have stated that."
He said it had not been necessary to "take soundings" within the party on the issue, as had been reported. "I think the party in the first 24 hours said its part. I think people are extremely annoyed about this and do believe that tax evasion is wrong and encouraging others to do it is equally wrong."
It was in this context that he confirmed that party officers would be meeting Ms Cooper-Flynn. He said she had asked to be allowed take a break and some time off until the weekend, and she had also wanted to wait for her legal advice once the costs issue had been determined. "That has now been done," he said.
Implying her time for decisions was running out, he added: "She also told us she would not wait long after that to make up her mind on an appeal."
The Labour Party leader, Mr Ruairi Quinn, welcomed the Taoiseach's criticism of Ms Cooper-Flynn's conduct but called on him "to match his strong words with appropriate action".
"It has taken almost two weeks for the Taoiseach to speak out in the terms we would expect from the leader of the Government, but apart from suggesting that party officers would be speaking to Deputy Cooper-Flynn this week, he gave no indication as to what action, if any, he is proposing to take."
"The people have a right to expect moral courage and political leadership from their Taoiseach. He should now show a little of both by taking decisive action in regard to Deputy Cooper-Flynn," he said.