Mr Ahern was not in court
Taoiseach Bertie Ahern has begun a High Court challenge to limit the work of a public inquiry probing planning corruption in the 1990s.
A legal team for the embattled premier told the three-judge sitting that papers sought by the Mahon Tribunal were protected by privilege.
The tribunal is probing Mr Ahern's personal finances.
Barristers are trying to prevent financial advice in relation to cash lodgements being disclosed.
Opening the case, Brian Murray SC, told the court his client was seeking legal and professional privilege over 150 pieces of communication with a banking expert, and parliamentary privilege over statements he made in the Irish parliament.
Mr Murray said Mr Ahern had also been seeking tribunal papers in relation to how banking staff calculated alleged foreign exchange transactions into his account.
However, shortly before the hearing began it emerged the tribunal had agreed to provide certain documentation.
"We will review that documentation during the course of the day and maybe when we have done so that third issue will be retouched," he added.
Mr Murray told the special divisional court - which sits only to deal with major cases of significant constitutional importance - that Mr Ahern had to hire the services of former Bank of Ireland currencies expert Paddy Stronge last April to contradict claims made by the tribunal.
The inquiry's banking witnesses had claimed funds lodged into Mr Ahern's account, and that of his former partner Celia Larkin in the 1990s were made up of $45,000 and £25,000.
Last September, Mr Ahern gave evidence to the tribunal disputing these hypothesrs and making reference to advice from Mr Stronge.
Mr Murray laid out five grounds why the tribunal could not order disclosure of the documents between the pair.
He said the taoiseach should have the same privilege as if he were a party in the High Court, litigation privilege over the advice was sought in response to an allegation, and legal privilege over all the correspondence.
Mr Ahern's legal team also rejected the tribunal's claims that there can be no privilege over the communications as it is inquisitorial and not adversarial.
The High Court challenge - heard by High Court president Justice Richard Johnson, Justice Peter Kelly and Justice Iarfhlaith O'Neill - is listed to last for three days.
Mr Murray is due to submit the taoiseach's case on Wednesday.