The Taoiseach Bertie Ahern has confirmed the Mahon tribunal is investigating payments he received in 1993.
Mr Ahern said he has provided the Mahon tribunal with bank details from the 1980s up to "very current periods" in connection with the inquiry.
The Irish Timesthis morning reported that businessman David McKenna has been contacted by the tribunal in connection with payments to Mr Ahern at the end of 1993.
Mr Ahern told Clare FM this morning the article was accurate and described the source as "impeccable", considering the information was given to the tribunal in a "confidential" meeting.
Mr Ahern said the tribunal was "rightly" investigating the matter.
However, he said the size of the payments in 1993 - reported to have totalled between €50,000 and €100,000 - were "off-the-wall".
"The only thing that I can say is that I was delighted to see the figures on the front of the paper. A lot of what is on the front of the paper is absolutely correct."
"I have co-operated throughout over the last number of years with them," Mr Ahern said this morning.
"What is in the paper this morning is some of the information I gave them in confidential session. Very confidential as you can see. And somebody has given it to The Irish Times.
"The source of the leak is absolutely impeccable," he said. "The person who gave the leak has obviously seen the full file, there is no doubt about that, except for the figures, the figures are off the wall."
The Mahon tribunal and Mr Ahern are due to make representations on the matter before the President of the High Court, Mr Justice Joseph Finnegan, next month.
The inquiries into Mr Ahern's finances are understood to have begun after allegations were made about supposed payments made to him by property developer Owen O'Callaghan in relation to the Quarryvale development in west Dublin.
The Taoiseach said this was an "old story" dating back to those allegations, some of which claimed he had received a payment of €15 million. Other payments of €1.5 million, €500,000, €60,000 and €30,000 were alleged.
Both Mr Ahern and Mr O'Callaghan have stated publicly that no such payments were made.
In December 1993, Mr Ahern was minister for finance and Fianna Fáil treasurer.
