The Garda fraud unit is investigating allegations that former government ministers had offshore accounts, Taoiseach Enda Kenny told the Dáil.

“They will make their decisions and follow through on that,’’ he said.

The Taoiseach was responding to Sinn Féin deputy leader Mary Lou McDonald, who read names from a dossier into the Dáil record.

She said it was not a case of her making allegations, “and I emphasise these are allegations”, adding they had come from a very credible source.

The whistleblower, she said, alleged that former ministers Des O'Malley (FF and later PDs), Ray MacSharry, Gerard Collins, Maire Geoghegan-Quinn (all FF), "an S Barrett" and Richie Ryan (both FG), as well as others, held offshore accounts. Mr MacSharry and Ms Geoghegan-Quinn served terms as EU commissioners.

Ceann Comhairle Sean Barrett intervened to ask Ms McDonald whether she was making allegations in the chamber.

She replied: “I am echoing the allegations that are very serious, that have been brought forward by the whistleblower.’’

Mr Barrett said Ms McDonald should know quite clearly, and if she had taken advice from the Clerk of the Dáil, that she could not name names of people who were defenceless to contradict her.

Mr Barrett urged Ms McDonald to brief herself on what she could and could not do in a democratic chamber.

“And I wish to state quite categorically, in case anybody is under any doubts, when you say ‘S Barrett’, it does not apply to me,” the Ceann Comhairle said.

Ms McDonald, who was speaking during Opposition Leaders’ Questions, said the whistleblower alleged matters of serious concern associated with very senior public figures.

“The whistleblower has told us very clearly that he has gone to every length to have these matters explored and investigated,’’ she said. “And the whistleblower now fears that will never happen.’’

She said the allegations of a serious nature had been made against named persons, and there was the more serious allegation that there was a connivance to avoid, or even cover up, the exposure of those matters.

Given that the Public Accounts Committee was not permitted to investigate those matters, she asked, what did the Taoiseach propose to do?

She also asked whether Minister for Enterprise Richard Burton would allow the whistleblower to complete the investigation, or whether Mr Kenny would propose another mechanism for the full examination of those issues.

Protect whistleblower

Mr Kenny said a law had been introduced for whistleblowers to bring forward certain matters they felt relevant to the public interest. The law was framed to protect the whistleblower.

He said the Garda fraud squad had made a formal request for a witness statement to be forwarded by Mr Bruton. The Minister confirmed it had been forwarded.

Earlier, Ms McDonald said the whistleblower was a senior civil servant and the authorised officer appointed to examine a scheme of tax evasion by senior political figures and of obstruction in the investigation and exposure of those wrongdoings.

"The whistleblower says his investigation into Ansbacher accounts, offshore accounts and tax evasion was terminated by the then minister, Mary Harney, in 2004, once Mr Desmond O'Malley was discovered to be one of the holders of those accounts,'' she said.

Ms McDonald said the whistleblower had reported that State agencies failed to investigate all of those matters thoroughly, including tribunals of inquiry.