The Coalition parties will today try to agree the wording of an amendment designed to water down a Fine Gael Dáil motion affirming confidence in the work of the Mahon tribunal.
Fianna Fáil sources have suggested that the motion should be amended to refer to the enormous cost of the Mahon tribunal and to the fact that it has not been able to prevent the leaking of confidential information.
Some Fianna Fáil figures have also be pressing for the inclusion of a reference to the possibility of limiting further inquiries into the Taoiseach's personal finances.
However, the Green Party and the Progressive Democrats are unlikely to agree to any wording that would either explicitly or implicitly criticise the tribunal's investigation into Mr Ahern's finances.
Both parties have repeatedly expressed full confidence in the Mahon tribunal and have said that it should be allowed to continue its work in the allotted time.
Crucially, the Government amendment to the Fine Gael motion will be proposed by the Green Party Minister for the Environment, John Gormley, as the Mahon tribunal comes under the remit of his department.
Discussions have already taken place between the Taoiseach's programme manager, Gerry Hickey, and the Green Party programme manager, Donal Geoghegan, on the wording of the Government amendment.
They will meet again today and possibly tomorrow to agree a wording so that it can be presented to the Cabinet for formal approval before the Dáil debate on Wednesday evening.
The Fine Gael motion, which will be moved by the party's environment spokesman, Phil Hogan, reads:
"That Dáil Éireann reaffirms its confidence in the Mahon tribunal, and its belief that the tribunal is acting independently, without bias and within the remit contained in the terms of reference set by the Oireachtas."
Mr Hogan said that the motion would allow all members of the Dáil and Cabinet to vote on a matter of huge importance.
"We will see if the Fianna Fáil ministerial attack dogs have any bite when it comes to this vote," Mr Hogan said.
"In addition, I look forward to John Gormley, Mary Harney and their party members voting in line with their publicly stated support for the Mahon tribunal," he added.
Fianna Fáil sources maintain that the Fine Gael motion will actually work in their favour by allowing them to state their reservations about the way the tribunal has gone about its work on the record of the Dáil and also by providing an opportunity to put down an amendment to the motion itself.
Under Dáil procedure the vote on the amendment to the motion is taken first and the Government's majority guarantees that its amendment will replace the Fine Gael motion.