Judgment in the challenge by Mr Charles Haughey to the Moriarty Tribunal will be delivered by the Supreme Court on Tuesday.
The former Taoiseach and members of his family are attempting to stop the tribunal investigating their financial affairs.
On April 28th the High Court rejected the challenge by the Haugheys and they appealed that decision to the Supreme Court. That court heard the appeal over several days and reserved judgment on July 1st.
The appeal was taken by Mr Haughey; his wife, Maureen; daughter, Eimear Mulhern, and sisters, Ethna and Maureen Haughey.
In the appeal, counsel for the Haugheys submitted fair procedures were not adhered to in relation to the making of discovery orders against bank and other accounts held by the Haugheys. They also raised constitutional issues regarding the Tribunals of Inquiry (Evidence) Act 1921 and whether the Taoiseach, Mr Ahern, had power to set up the Moriarty Tribunal, chaired by Mr Justice Moriarty.
In his High Court decision on the matter, Mr Justice Geoghegan said that in the light of the findings of the McCracken Tribunal on payments to politicians, it was "bordering on the absurd" for Mr Haughey to claim he was being discriminated against by the Moriarty Tribunal as compared with other ex-Taoisigh, ex-Ministers or ex-TDS or other holders of Ansbacher accounts.
Mr Justice Geoghegan said: "The position of Mr Haughey in public life, the nature and the amounts of the gifts given to him by Mr [Ben] Dunne, and the lifestyle evidence singled him out and he cannot complain, in my view, that he is in some way or other being discriminated as against others."
There were clearly questions of public concern as to the ethical behaviour of Mr Haughey, added the judge.
The High Court held that Mr Haughey's wife, daughter and two sisters should have been given a reasonable opportunity to object to the tribunal's orders directing discovery of their bank accounts.
It also found that Mr Haughey and his family were entitled, if they so requested, to a prima facie explanation from the tribunal of any relevant ambiguities in its terms of reference.