The Morris Tribunal will rule next week on efforts to force two politicians to disclose the source of allegations they made regarding garda corruption in Donegal.
Fine Gael Senator Jim Higgins and Labour Party TD Brendan Howlin have argued that they cannot be forced to reveal their sources and would be compromised as public representatives if they did so.
Lawyers for the Morris Tribunal, however, have claimed that they need to know the source of the allegations if a full investigation is to be carried out.
The allegations of garda corruption were passed to Mr Higgins and Mr Howlin in June 2000 and both men agreed not to reveal the source of the claims.
However, they passed the information on to then Justice Minister John O'Donoghue as part of ongoing investigations into allegations of widespread corruption in Donegal.
The allegations are believed to have been so serious that they were one of the main reasons why the Government subsequently established the Morris Tribunal.