Members of the Oireachtas committee on abortion will be not allowed to rotate their positions with other party members.
The names of the members of the Joint Committee on the Eighth Amendment of the Constitution, which will be tasked with considering the recommendations of the Citizens' Assembly, were due to be submitted to the Ceann Comhairle this week but have not yet been finalised.
One of the committee’s main tasks will be to formulate the wording of a referendum.
Some parties had wanted to change members’ positions on a weekly basis.
The Dáil’s business committee met on Thursday to discuss the composition of the committee but there has still not been agreement on the numbers.
Ceann Comhairle Sean O’Fearghaíl said the Seanad had voted to elect seven members and were unwilling to change that number.
He told the meeting he had discussed this with the Cathaoirleach of the Seanad Denis O’Donovan but no resolution had been identified.
Mr O’Fearghaíl proposed reducing the number of TDs on the committee to 15 and Senators to six.
Fine Gael has yet to decide its membership of the committee but Dublin Bay South TD Kate O'Connell and Kildare North Bernard Durkan have committed to participating.
Mr O’Fearghaíl told the meeting members would not be allowed to rotate their positions.
Solidarity and People before Profit had sought to change positions on a weekly basis while the Social Democrats, the Greens and Séamus Healy, the Workers and Unemployed Action Group TD had asked for a similar situation.
Three members of the Civil Engagement Group, an alliance of Independent Senators, had asked to rotate their seat on the Joint Committee on the Eighth Amendment to the Constitution.
The original plan was to have 16 TDs and four Senators on the committee, but the Seanad has pushed for seven representatives. If the committee had 20 members as originally planned Fine Gael would have five TDs and one Senator among its members.
Both Fine Gael and Fianna Fail have been granted a free vote on abortion for the first time, which allows them to vote according to their own beliefs rather than following a party line.