The High Court has begun hearing an action by former Fine Gael Minister Michael Lowry challenging a decision by the Moriarty Tribunal refusing him two thirds of his costs of engaging with the inquiry.
Lawyers for Mr Lowry said his overall costs bill was "vast" and would amount to amount to several million euro.
The tribunal was set up in 1997 to investigate payments to Mr Lowry and former Fianna Fáil Taoiseach the late Charles Haughey.
It decided to award him just one third of his costs arising from its finding that he had failed to co-operate fully with it.
Mr Lowry, who is now an independent TD for Tipperary North, claims he is being discriminated against in comparison to Mr Haughey who was awarded his full costs.
In court this morning Senior Counsel Niamh Hyland the core issue was the disparity of treatment between Mr Haughey's costs and Mr Lowry's.
She said the tribunal did not adhere to its own rules when determining Mr Lowry's costs.
She said the tribunal lasted 14 years having been set up in 1997 and for all of that period, although there were different phases and different levels of intensity of engagement, Mr Lowry was the subject of matters considered by the tribunal.
The costs have been vast and run into millions, she said.
She said the report of the tribunal found in the course of his office as Minister, Mr Lowry had conferred a benefit on Mr O'Brien and that the businessman had made or facilitated payments to Mr Lowry, but there was no finding that he benefited from those payments which was in stark contrast to the findings against Mr Haughey.
She said the conclusions of the tribunal were wholly an unambiguously rejected by Mr Lowry but it was also clear that the findings do not have any legal force and have no legal effect.
They were described in other proceedings as "sterile legal findings". She argued that it was disproportionate to come up with this figure having regard to his extensive level of cooperation with the tribunal.
She said this was the only legal action taken by Mr Lowry against the tribunal compared to other actions by Mr O'Brien and Mr Haughey.
The awarding of the mobile telephone licence to Esat took up 70% of the tribunal and it had not identified any difficulties or gaps in his assistance with that part of the tribunal yet he had come away with one third of his costs.
She said there was an inequality in how the tribunal addressed the matter of costs with regard to Mr Lowry.
As a matter of law there was an obligation to treat people similarly situated, equally she said adding that there ought to have been the same procedure applied to Mr Lowry and Mr Haughey.
"When you set up a system for adjudicating costs everyone must go through that gateway," she said.
She said the reasons given by the tribunal was that he had failed to identify one bank account in the Isle of Man, which he dispute, and that he had "set about an implemented a course of furnishing to the tribunal falsified documents".
She said they would be asking the judge to look in some detail at that because "we say there is simply on evidence in respect of the charge of furnishing falsified documents.
At the height of the tribunal's case is identifying a motive for doing so."
The third point related to a finding by the tribunal that he had with the accountant Denis O'Connor, orchestrated an agreement with a certain person to ensure they engaged in correspondence to mislead the tribunal.
"We say there is effectively no evidence that he was engaged in any orchestration of agreements," Ms Hyland said.
She said the tribunal failed to apply its own test of "beyond doubt" when making its findings in relation to costs as its decision was made on the basis of its findings, which were based on "reasonable opinion".
Instead the tribunal should have started again and applied the beyond doubt standard, she said.
"They should have changed the lens they were using they did not do that and simply referred back to the previous report.. so they fell into error at that point."
Ms Hyland said the tribunal has sat in public for 384 days and 240 of those days were relevant to Mr Lowry.
70% of the tribunal concerned the awarding of the mobile phone licence and 30% with the so called "money trail" module.
She said an adverse finding on costs could only apply to the money-trail section and could therefore only apply to one third of his costs.
She said findings of wrongdoing cannot form the basis for an adverse finding in relation to costs. The substantive outcome of the tribunal was being used to influence the question of costs and this was incorrect, she said.
It was not like a court case where the losing party must pay the costs. In the case of tribunals it was the direct opposite and tribunals were not allowed to do that, she said.
Ms Hyland said they were not seeking to challenge the findings of the report but the seeking to challenge the findings it made in relation to costs.
The case continues before Mr Justice Hedigan.
