The Revenue Commissioners have been allowing people who made false declarations when availing of the 1993 tax amnesty to privately settle their tax affairs instead of being prosecuted.
This is despite the offence carrying a penalty of up to eight years in prison, and the amnesty having been presented at the time as a "last chance" for tax cheats.
The Taoiseach, Mr Ahern, who was the minister for finance in 1993, said when he introduced the amnesty those who abused it would be detected and pursued.
"It is time we started jailing people, and, quite frankly, I look forward to that day," he said in June 1993.
A spokesman for the Revenue Commissioners said it made a decision not to prosecute people who made false declarations because it believed it did not have the level of proof needed to secure a criminal conviction, which is higher than that needed in a normal revenue investigation.
About 20 parties suspected of making false declarations under the controversial amnesty have been identified by Revenue, the Minister for Finance, Mr McCreevy, said in a parliamentary reply this week. Investigations progressed in one-third of these cases with the permission of the appeals commissioner.
However, The Irish Times has established that none of these has been prosecuted by Revenue to date.
The amnesty legislation included a 10-year statute of limitations, so the cut-off date for criminal proceedings has now passed.
It is now likely the only person who will face criminal charges under the 1993 amnesty is the former minister for justice Mr Ray Burke. The Criminal Assets Bureau is pursuing the case against Mr Burke.
The amnesty legislation - Waiver of Certain Tax, Interest and Penalties Act, 1993 - prevents revenue officials from getting access to declarations made under the amnesty.
Those who made false declarations would normally only be discovered during the course of a Revenue audit or investigation if the amnesty declaration is produced to the auditor or investigator.
In such cases where Revenue suspects a false declaration has been made, the consent of an independent appeals commissioner is required to pursue the matter.
Mr McCreevy confirmed that "approximately 20" applications have been received by the appeals commissioner, and consent to further investigate has been granted "in about one-third of these cases".
Some of these investigations have not reached a conclusion, but it is understood others have been closed following the payment of settlements.
Mr McCreevy's reply and the passing of the 10-year period suggests the former minister for communications Mr Michael Lowry no longer faces the threat of criminal prosecution under the 1993 amnesty law. Mr Lowry told the Dáil in 1996 that he had availed of the 1993 amnesty, and also conceded that in the 1992-93 tax year he received £208,000 from Dunnes Stores, which he conceded was not declared for tax purposes. To comply with the amnesty he would have had to have filed a full and accurate declaration for the 1992-1993 tax year.
Mr McCreevy released the information in response to a parliamentary question tabled by Mr Paul McGrath TD, Fine Gael's deputy spokesman on finance.
Mr McGrath said the failure to pursue criminal charges against parties who made false declarations was not in keeping with what was envisaged in the 1993 legislation.
"You'd have to ask why the Revenue thinks it hasn't got the proof to pursue criminal charges. How would it know if it never tried? I would say that making those kinds of judgments is not even the role of Revenue."
At the time the amnesty was strongly opposed by opposition parties, and the Government stressed that there would be harsh penalties for abuse of the measure. The PDs described it as a "bonanza for tax cheats".
