INDEPENDENT TD Michael Lowry says a payment referred to in a taped conversation with a land agent was declared for tax.
But the Revenue Commissioners can't back up his claim as it says it does not comment on individual cases.
A recording of a telephone conversation between the disgraced former Fine Gael minister and Northern Ireland-based land agent Kevin Phelan was obtained by the 'Sunday Independent'.
A sum of Stg£250,000 that Mr Lowry said he paid to Mr Phelan is central to the colourful conversation. Mr Lowry said on the tape: "I never declared it."
The conversation took place on September 30, 2004.
A copy of the tape has been passed by the newspaper to the Criminal Assets Bureau but the Garda Press Office had no comment to make.
A government minister showed a lack of interest yesterday in the latest revelations.
Transport Minister Leo Varadkar said he no longer followed the affair.
"I have stopped reading those stories at this stage," he said.
But he did say he found it disturbing to see footage from the 1990s of Mr Lowry in the ministerial offices Mr Varadkar now occupies. In a statement last night, Mr Lowry said the payment in question was made by his company on his behalf.
"That transaction was properly recorded and accounted for in the records and accounts of Garuda Limited. The payment referred to is fully tax compliant," he said.
The telephone conversation was recorded by Mr Phelan and supplied to the 'Sunday Independent' by him.
Mr Phelan is a property consultant based in Omagh, Co Tyrone. His business includes identifying land parcels for purchase and development and then identifying suitable investors. A number of these deals were probed by the Moriarty Tribunal, but Mr Phelan declined by fax to appear as a witness at the last moment.
Since he is based outside the jurisdiction, he could not be compelled to attend.
In the recorded conversation, Mr Lowry constantly refers to a sum of either Stg£200,000 or Stg£250,000, which he said he paid to Mr Phelan and which the land agent confirmed he received.
Mr Lowry appeared extremely anxious to get Mr Phelan to confirm that he had nothing to do with an entity called Glebe Trust, described in the conversation by Mr Phelan as his "family trust".
The Moriarty Tribunal, in its final report, said it could make only limited findings on one of the deals set up by Mr Phelan – the sale of Doncaster Rovers, an English third-division football club in 1998 for Stg£4.3m – because of the "suppression" of evidence. The tribunal made a number of adverse findings against Mr Lowry.
In his statement, Mr Lowry also referred to his dealings with the McCracken Tribunal and Moriarty Tribunal.
The tribunals examined his business relationship with Ben Dunne and the awarding of a mobile phone licence to a consortium headed by Denis O'Brien.
"My business dealings have been the subject of intense scrutiny over a prolonged period leading to several false and inaccurate reviews," Mr Lowry added.
Mr Lowry again said he had nothing to do with the Glebe Trust. "The Register at the UK Land Registry and company records clearly show that I never had any direct or indirect shareholding or beneficial interest in Doncaster Rovers or its associated companies. I also confirm that I never had any material or beneficial interest in 'Glebe Trust'."