The opposition has held back on calling for the resignation of the Fianna Fáil TD Mr Michael J. Collins until it learns whether statements he made last year to the Standards in Public Office Commission were truthful.
The Fine Gael TD Ms Olivia Mitchell said: "This concludes a bad week for Fianna Fáil and, more importantly, a bad week for politicians and politics in this country.
"The challenge of engaging the public in the political process was made even more difficult this week with a series of events that has cast a pall over politics and the work of politicians generally."
Ms Mitchell added: "Opinion poll after opinion poll indicates a growing detachment of the public from the political process - and with the events of the last week it is not difficult to understand why."
Opposition politicians could easily call on the Limerick West TD to express "shock", "horror" and to call on him to "consider his position" - the usual code used for a resignation call, she noted.
"What is more difficult is to rebuild a sense of trust in the political process and to engage the public on matters that affect them. That is the challenge that my colleagues and I in Fine Gael are determined to take on."
However, she said, it appeared that he had settled with the Revenue Commissioners in the second quarter of this year for more than €100,000, nearly a year after the general election.
"This must raise questions about documentation that he submitted to the Standards in Public Office Commission, and we expect that that office will be investigating these issues," Ms Mitchell said.
Labour's spokeswoman on finance, Ms Joan Burton, said Mr Collins "now joins a growing list of prominent members and supporters of Fianna Fáil who have been exposed as tax cheats".
Tax evasion was "almost endemic in Irish society at one stage and still remains a significant problem. Clearly many in Fianna Fáil believed that tax was something that should be paid only by 'the little people'," she said.
The publication of the defaulters list by the Revenue Commissioners was "a stark reminder of the extent to which many of the great and good in Irish society unlawfully evaded paying their fair share of taxation".
Ms Burton wanted to know what action was taken by Fianna Fáil before the general election to make sure all election candidates were fully tax-compliant.
"When did Deputy Collins's tax-evasion first come to the attention of the Taoiseach and the Fianna Fáil leadership? What action does the Taoiseach now intend to take?" she asked.
Mr Collins had questions to answer, including the length of time the offshore account was open and if he availed of the 1993 tax amnesty.
"He should state why he did not respond to previous directives from the Revenue Commissioners for offshore account-holders to come forward," she said.
Ms Burton said the Revenue Commissioners had "a miserable record" of using criminal law to prosecute tax fraudsters. The problem seemed to be an institutional attitude rather than a defect in legal power. Instead, the Revenue saw its function as raising money for the Exchequer, including using penalties and charges.
Evidence given to a number of tribunals showed that some people must have broken the 1992 tax amnesty by "failing to apply for it, which is itself an offence, or by failing to make full and frank disclosure", Ms Burton said.
The public would not believe there was "a fair and impartial system of justice in this country unless and until those who defraud the tax code are pursued as relentlessly as those who defraud the social welfare".