Fianna Fáil's internal investigation into Limerick West TD, Mr Michael Collins, who was named as a tax defaulter last week, will begin this week despite his resignation on Saturday from the Fianna Fáil Parliamentary Party.
"He is still a member of the Fianna Fáil party and is, therefore, subject to the discipline of the party. That is no less important after his decision to quit the party whip," said a party spokesperson.
Clearly embarrassed by the latest controversy, Fianna Fáil's rush of activity has done little to hide the fact that senior figures have known for weeks that the Patrickswell-based deputy was about to be identified by the Revenue Commissioners.
Mr Collins contacted the Government Chief Whip, Ms Mary Hanafin, shortly before 6 p.m. on Saturday to tell her that he was 'voluntarily resigning' from the Parliamentary Party.
Promising to 'co-operate fully' with Fianna Fáil's internal inquiry, Mr Collins, who has had to pay €130,000 in taxes and penalties to the Revenue, said: "I express my deep regret and embarrassment concerning recent disclosures."
However, he made it clear that he would not quit the Dáil: "I intend to fulfil the electoral mandate given to me by the people of West Limerick by continuing to serve their interests in Dáil Éireann."
Furthermore, Mr Collins again claimed that he had "complied at all times with the legal requirements which are laid down" by the State-appointed Standards in Public Office Commission.
Under electoral laws, TDs must secure a tax clearance certificate from the Revenue Commissioners within nine months of a general election, and swear an oath that they are in compliance with tax laws.
Mr Collins' insistence that he has obeyed these laws caused confusion amongst colleagues: "I don't see how he could have got tax clearance from one part of Revenue if another part of it was chasing him for money," said one FF TD.
Under Fianna Fáil's rules, Mr Collins could be asked to quit his Dáil seat by a two-thirds majority of the party's National Executive - but there is unlikely to be much enthusiasm for this course of action.
Fine Gael TD Mr Gay Mitchell said Mr Collins' resignation of the party whip "did not matter a jot", adding: "He remains as an Independent Fianna Fáil TD and will vote with FF."
The Minister for Justice, Equality and Law Reform, Mr Michael McDowell, rejected charges that the Progressive Democrats have adopted a softly-softly approach to Mr Collins.
"I think it is embarrassing both for politics and for the Government as a whole that some of its backbenchers have been implicated in these events," he told RTÉ's Week in Politics programme last night.
However, he said a majority of TDs in Dáil Éireann do not have the power to demand the resignation of a colleague, since that person's mandate flows from the voters.
Former Fine Gael Cabinet Minister Mr Michael Lowry's conduct had been "on the same moral plane" as Mr Collins, yet Tipperary North voters had felt it right to re-elect him, Mr McDowell said.
Demanding a Dáil debate into tax clearances, Green Party TD Mr Dan Boyle said the Revenue had said on Friday that it was "obliged" to issue such documents if people declared that their affairs were in order.
He said he wanted the Government to clarify the exact status of tax clearance certificates given to TDs by the Revenue Commissioners.
"Are these tax certificates only valid for the last tax year or do they imply full tax compliance? If not then this tax clearance system for TDs cannot inspire public confidence.
"I am calling for a full Dáil debate on the issue and I am challenging the government to put in place the necessary measures to close any such loopholes," Mr Boyle said.