Companies associated with the Ansbacher deposits have been so unhelpful to officers of the Moriarty tribunal that it may never be possible to outline fully how the accounts operated, according to one of the tribunal's senior counsel.
Mr John Coughlan SC said obtaining information from the Cayman Islands had proved very difficult.
He said the tribunal had been in correspondence "with the entities which formed part, at one time or another, of the Ansbacher operation.
"The response of those entities to the requests from the tribunal for assistance has proved to be unhelpful and in some cases more than unhelpful."
He said the response of Hamilton Ross in particular had been "wholly obstructive".
Earlier, Mr Justice Moriarty said that because of the additional information that had been made available to the tribunal "a further amplification of those terms of reference has become necessary".
When he had last outlined his understanding of the terms of reference in 1998, the tribunal had been focused on Mr Charles Haughey and Mr Michael Lowry.
However, looking at the terms of reference as a whole and the recommendations the tribunal had been asked to make, it was clear the ambit of the inquiry in relation to the Ansbacher accounts was wider than Mr Haughey's involvement in those accounts, Mr Justice Moriarty said.
The chairman said the expression "public office" in the terms of reference had a wider application than the expression "ministerial office" used elsewhere in the terms of reference.