Fine Gael may refuse to co-operate with the Government on Dáil business if the party is refused proportional representation for the roles of chairman and vice-chairman of parliamentary committees.
The party has submitted proposals to the Government to apply the D'Hondt system, used in the North, the European Parliament and most EU member states, where the chairman, vice-chairman positions and committee membership is allocated to parties based on the number of seats they hold.
The Opposition has already complained that no committees have been established despite a three months' recess and Government backbenchers are equally anxious that the appointments be made for the coveted positions.
Fine Gael has complained that it has received no response to its proposals made to Government weeks ago. Non co-operation on Dáil business could include refusing to allow "pairing" for Ministers away on official business and calling quorums during Dáil debates.
Party leader Enda Kenny raised the issue in the Dáil this week and Tánaiste Brian Cowen said discussions had started between Government chief whip Tom Kitt and the Opposition whips, with the aim of reaching a consensus next week.
The Government is aware of Fine Gael's threatened non-co-operation, and Taoiseach Bertie Ahern is understood to be finalising over the weekend with Mr Kitt which committees will be established - including any new ones. However, membership and leadership is unlikely to be announced until next weekend at the earliest.
In the last Dáil there were 20 committees including 14 select committees which dealt with legislation.
Fine Gael, as the largest opposition party has traditionally had leadership of just two committees, Public Accounts and the European Affairs, although membership is allocated proportionately.
Fine Gael chief whip Paul Kehoe insisted that "it is essential Fine Gael's greatly increased electoral mandate is reflected in the new committee structure".