The Taoiseach, Mr Ahern, has written to the Fine Gael leader, Mr Bruton, last night advising him that the Government is not in a position to publish information contained in the report of the Tanaiste's authorised officer, Mr Gerard Ryan. He was responding to a call for publication of the 120 Ansbacher names.

To publish the names would be an offence under Section 21 of the Companies Act 1990 and would amount to a conscious contempt of court, the Taoiseach said.

"The Government is advised that the 1990 Act does not permit the publication of information obtained under Section 19 on a "name and shame basis" according to the letter.

In the Dail today, a Fine Gael motion seeking such a move is to be debated. The Government has moved an amendment to the motion which restates its opposition to publication. In his letter, Mr Ahern said his advice was that making Mr Ryan's report public would infringe the Constitution and seriously jeopardise any prosecution on foot of the current investigations.

Section 21 of the 1990 Act notes that the report may only be published by, or disclosed to, "a competent authority", which includes the Tanaiste, the Minister for Finance and the Central Bank. The Tanaiste also has the authority to provide other people with the report. She has already used this authority to give the Taoiseach and the Attorney General copies of the report.

The report has also been given to the six directors of Ansbacher (Cayman) Ltd and the financier, Mr Padraig Collery, who succeed the late Des Traynor in managing the Ansbacher accounts.

The six directors are Mr Hugh Cecil Hart, Mr John Bryan Rothwell, Mr John Anthony Collins, Mr Peter Neville Seaife, Mr Garry Crossan and Ms Beverley Ann Hodkin. Last night, Ms Hodkin and Mr Rothwell declined to comment on the continuing controversy. From the Cayman Islands, Mr Rothwell told The Irish Times he "could not comment on the matter at this time".

Mr Bruton said the fact that a selection of names from the Ansbacher list had been released to The Irish Times vindicated his call to the Tanaiste to change the law to allow for the release of the list "in a planned and structured way".

"No fair-minded person could possibly believe that this process of surreptitious, partial and probably malevolent leaking is the way to deal with this report. The way to deal with it is to change the law to allow its release in full, with notice, at an early date this week or early next week."

Mr Bruton wrote to the Tanaiste appealing to her to change the law and asked her what steps she had taken to establish the likely source of the leak to The Irish Times.

Meanwhile, the Labour Party confirmed yesterday that it would be supporting the Fine Gael motion in the Dail to pave the way for the publication of the list.

The Labour Party spokesman on finance, Mr Derek McDowell, called on the Tanaiste to publish the legal advice received by the Government which says the law cannot be changed to allow for the publication of the full list of names of Ansbacher account holders. He said the publication of names in The Irish Times eroded the credibility of the Government's position.