Businessman Denis O'Brien is considering two substantial challenges to the inquiry by the Moriarty tribunal into the State's second mobile phone licence competition.
The tribunal is coming near the end of its marathon examination of the licence competition, which was won by Mr O'Brien's Esat Digifone in 1995.
The tribunal is also inquiring into whether Mr O'Brien gave financial assistance to the then government minister, Michael Lowry, who oversaw but had no role in, the licence competition.
On Tuesday Mr Justice Moriarty, the tribunal chairman, issued a ruling stating that he would not be calling economist Dr Peter Bacon to give evidence.
Dr Bacon was commissioned by the tribunal at the outset of its inquiry to prepare a report for the tribunal on the competition process. It was not until a number of years later that persons who appeared before the tribunal learned of the existence of this report.
Some time ago Mr O'Brien launched an unsuccessful High Court challenge seeking to prevent Dr Bacon being called by the tribunal, as it had earlier indicated it would do so.
Mr O'Brien was opposed successfully in the courts by the tribunal.
Mr O'Brien, in a statement yesterday, referred to this: "Mr Justice Moriarty now accepts that Mr Bacon is actually not an 'expert witness' and that my position was correct all along. I note that the tribunal did not have the good grace to acknowledge this matter in its ruling," Mr O'Brien said.
Witnesses who were questioned about the competition process were not told about Dr Bacon's report before giving evidence.
Mr O'Brien said the consequences of an alleged failure to abide by proper procedures and due process "remain unaddressed".
Mr O'Brien, in his statement, also referred to other aspects of the licence inquiry which he said were flawed.
He said none of these "fundamental procedural flaws on the part of the tribunal and the resultant serious (possibly fatal) impact on all of the evidence given to date before the tribunal in respect of the licence process" were addressed in Mr Justice Moriarty's ruling.
"As stated at the outset, I am considering the ruling in detail and reserve all of my rights in relation to any further submissions and/or further action that may be merited and required arising from this ruling and related matters."
Mr O'Brien said he was also reserving his position on the rules of evidence at the tribunal.