Lobbyist Frank Dunlop has said that he discussed with then minister for transport Brian Cowen the "political pedigree" of a businessman who was seeking a right of way across State property to allow for a commercial development.
Mr Dunlop said that this issue arose at a meeting with the minister in October 1993 as the businessman concerned was from "a Fianna Fáil family".
Resuming evidence at the Mahon tribunal yesterday, he said that the father of businessman Michael McGuinness would have been a contemporary of Mr Cowen's father. He said that both men would have served together on local authorities.
"He [ Mr Cowen] knew Michael McGuinness and who he was and where he was coming from," Mr Dunlop stated.
Mr McGuinness's father was a long-serving councillor in Kilkenny. His brother, John McGuinness, is a Fianna Fáil TD.
Mr Dunlop said that he had been retained by Mr McGuinness to lobby on behalf of the Cargobridge consortium, which owned 24 acres near Dublin airport.
Mr Dunlop said that he did not know that one element of the Cargobridge consortium had been part-owned by Ciarán Haughey, the son of the former taoiseach, Charles Haughey. He said that this issue had never been mentioned with Mr Cowen.
He said that only two issues had been discussed with Mr Cowen, the matter of Mr McGuinness's "political pedigree" and the right of way.
Meanwhile, the tribunal also heard that in an internal memo drawn up for the Cargobridge consortium Mr McGuinness described Mr Dunlop as his "middleman" with Mr Cowen.
The tribunal was told that following his meeting with Mr Cowen in October 1993, the lobbyist had told Mr McGuinness that the minister had shown him a draft letter in which he agreed in principle to grant a commercial right of way.
The tribunal also heard that in December 1994 Mr Dunlop had acquired within days of it being sent, a letter from Mr Cowen to the then Aer Rianta chairman, Noel Hanlon, directing him to examine the matter of the right of way.
Mr Dunlop said yesterday that he had either received this letter from Mr Cowen or from someone in his private office.
He said that he had no recollection of discussing with Mr Cowen or any of his officials the issue of the rezoning of the Cargobridge land by Dublin County Council in 1993.
However, he said that he had phoned the minister in Brussels in early October 1993 regarding a letter sent by the Department of Transport to Dublin County Council expressing safety concerns about planned rezoning motions for land near the airport.
He said that Mr Cowen had denied knowing anything about the letter. Mr Dunlop said that he told the minister that the letter was "causing mayhem" among the Fianna Fáil councillors who viewed it as an attempt by Aer Rianta, which opposed the planned rezonings, to get the department to encourage the council to oppose the motions. Mr Dunlop said that the letter had subsequently been withdrawn.
Meanwhile counsel for Fianna Fáil senator Don Lydon, Séamus Ó Tuathail, said that Mr Dunlop had made seriously defamatory comments about his client at a private interview with the tribunal in 2000 but that four years later in a formal statement he had omitted his name from those alleged to have received payments.
Mr Dunlop said that the original statement he had made in relation to Senator Lydon had been wrong.
However asked to apologise to Senator Lydon, Mr Dunlop said that he would not.
"I don't do apologies," he said.