Taoiseach Bertie Ahern assisted a Manchester-based businessman to obtain an Irish passport in 1994, it emerged tonight.
However, Mr Ahern's spokesman denied any "sinister" motive behind the issuing of the passport and said any member of the Oireachtas could assist someone to obtain a passport within five days.
A passport issued to Norman Turner, a businessman involved in the Sonas consortium which planned to develop the Phoenix Park racecourse as a casino, was returned via Mr Ahern's office, Fine Gael established through Dáil questions.
Phil Hogan, Fine Gael
Fine Gael environment spokesman Phil Hogan tabled parliamentary questions which reveal that a passport issued to Mr Turner on Tuesday August 9th 1994 was "returned through the office of Mr Bertie Ahern TD".
Mr Hogan said this "close relationship" with Mr Turner is "completely at odds with the Taoiseach's continuous claim that he opposed the casino project in Government and in opposition".
In December, Mr Ahern dismissed claims that he gave implicit approval to the National Lottery to enter talks with Mr Turner about becoming involved in his plans for a casino in Dublin.
Mr Ahern was minister for finance at the time of the talks in the early 1990s and had political responsibility for the lottery. The contacts did not lead to a formal deal between the lottery and Mr Turner's group Sonas, whose plans for the site of the former Phoenix Park racecourse were backed by US casino firm Ogden.
The rejection of the claims by Mr Ahern's spokesman conflicted with the account of former National Lottery chairman John Hynes, who said that he would not have entered talks without implicit approval.
The Mahon tribunal has previously heard that Mr Turner gave $10,000 in 1994 to Des Richardson, then chief fundraiser for Fianna Fáil.
Mr Hogan said the timing of the issuing of the passport "is significant given what we now know about financial transactions involving Mr Ahern and his associates during 1994".
"The Taoiseach must now make a full and honest statement about his relationship with Mr Turner. This new information also raises new issues for Mr Gormley and Ms Harney and they must confront Mr Ahern with this new information," Mr Hogan said.
"I will be passing this information to the Mahon tribunal to assist them in their enquiries. I also intend returning to this matter in the Dáil tomorrow where we continue to debate the Government's attempts to undermine the Mahon tribunal."
Asked about the matter tonight, a spokesman for Mr Ahern said: "The Taoiseach, in common with many other members of the Oireachtas, facilitated passport applications by people who were legally entitled to hold an Irish passport. This application was no different.
"Norman Turner's mother was born in Cork in 1927, therefore Mr Turner was legally entitled to hold an Irish passport. The suggestion of a sinister and inappropriate motive is wrong and totally mischievous."
The spokesman said the five-day turnaround time for the Department of Foreign Affairs to issue passports was "available to all members of the Oireachtas".
He said all TDs and senators could avail of it and that 6,200 such passports were issued under the same scheme last year.
The Mahon tribunal is investigating a number of transactions relating to bank accounts operated by, or for, Mr Ahern in 1993 and 1994 when he was Minister for Finance.
These include a loan of £19,115.97 taken out by Mr Ahern on December 24th, 1993; a lodgement of £22,500 made to a special savings account on December 30th; a lodgement of £27,164.44 to the same special savings account on April 25th, 1994; a lodgement of £2,835.56 made to a current account on the same day; a lodgement of £20,000 to an account in the name of Mr Ahern's daughters on August 8th, 1994 and a lodgement of £24,838.49 made to Mr Ahern's account on October 11th, 1994.
The tribunal says the transactions in question are largely undocumented.