The former assistant Dublin city and county manager, Mr George Redmond, has been refused the bulk of his legal costs for the Gogarty module.
However, the chairman, Judge Alan Mahon granted Mr Redmond costs for eight private interviews he attended at the tribunal.
"I was unable to identify any indication of substantial co-operation on the part of Mr Redmond, insofar as the substantive issues under investigation were concerned. The extent of the unreliability of Mr Redmond as a credible witness is such as to render it impossible for me to justify an order directing his costs be paid by the State," he said.
The exception was in what Judge Mahon described as one relatively small but important aspect of the tribunal's investigations when Mr Redmond attended the private interviews. Other than that, he was refusing Mr Redmond his costs.
"In addition to the serious findings of non-co-operation, hindrance and obstruction made against Mr Redmond, the tribunal also made a number of adverse findings on the substantive issues under investigation, including findings of corruption," the chairman said.
Before the rulings, Mr Redmond, representing himself, cross-examined Mr Jude Campion, a former employee in a Dublin amusement arcade, who gave evidence that Mr Redmond, Mr Liam Lawlor, and solicitor Mr John Caldwell attended the office of developer Mr Jim Kennedy upstairs in the premises from 1988 to 1990. He said Mr Redmond had frequented the premises daily for months and was hardly ever out of the place.
Mr Redmond replied he did not deny he had visited Mr Kennedy there, as he knew him reasonably well, but his visits were not frequent and only on weekends. He was always alone. If he went to look for Mr Kennedy, he would go to the basement, never upstairs, he stated.
Mr Redmond denied that Mr Lawlor and Mr Caldwell attended any meetings with him and Mr Kennedy. He added that Mr Caldwell and he had never met.
He said he retired in late 1989 from the council, so it was not possible for him to have any influence over anything a year later.
For his part, Mr Campion said Mr Kennedy had told him Mr Redmond had retired but had trained in a lot of people on the council to do his type of work and was still a very powerful man.
Mr Redmond countered: "Did you think I was a sort of Svengali with power over people?"