Labour leader Pat Rabbitte is to be called as a witness at the tribunal over his receipt of a cash donation from Frank Dunlop one week after he supported a controversial rezoning in 1992.
Mr Rabbitte, who was then a Democratic Left TD, returned the donation by cheque three weeks later.
He supported the rezoning of land at Ballycullen in south Dublin after being lobbied by Mr Dunlop and the landowner, Christopher Jones, the tribunal heard yesterday.
Patricia Dillon SC, for the tribunal, said documentation showed there was contact between Mr Jones and Mr Rabbitte in connection with the lands, and between Mr Dunlop and Mr Rabbitte.
After the October 29th, 1992 vote, Mr Jones wrote to Mr Rabbitte thanking him for his support.
On November 5th, after a general election had been called, Mr Dunlop travelled to the politician's house and made a cash donation. He has claimed the contribution, which he said was for £3,000, was readily accepted.
Mr Rabbitte has told the tribunal he received £2,000 in an envelope and resolved, as soon as Mr Dunlop had left, to recommend that Democratic Left return the money. This was done on December 17th.
Ms Dillon said there was no dispute that money was paid and no allegation of corruption in connection with the payment.
However, she pointed out that Mr Dunlop had previously told the tribunal that payments made by him in cash were corrupt. The tribunal was anxious, therefore, to explore with him the nature of the payment to Mr Rabbitte.
Mr Dunlop had a chance meeting with Mr Rabbitte in Brown Thomas after the tribunal was set up, he has told the tribunal. The politician informed him that he had received a letter from the tribunal and said he presumed "the matter would never come up". Mr Dunlop took this as a reference to the donation.
It also emerged yesterday that Tánaiste Mary Harney met Derry Hussey, financial controller of the Jones Group, in 1991 and 1992 in connection with the lands. At the time, she was a minister of state and Ballycullen was in her constituency. Although a member of the council, she did not attend the meeting at which the land was rezoned.
Ms Harney has told the tribunal she does not recall the details of her discussions with Mr Hussey. This is no allegation of impropriety on her part, counsel said.
Mr Dunlop received more than three times the amount he says he got from Mr Jones, it emerged during his direct evidence yesterday.
Ms Dillon said the lobbyist had told the tribunal he got £17,500 from Mr Jones. In fact, the real sum was almost £60,000. She asked how the witness could have got it so drastically wrong.
Mr Dunlop accepted there was a "dramatic difference" but said he was unable to explain it. He denied deliberately understating the amount to minimise his tax liability.