Sinn Féin is today urging the two Government-appointed senators to quit the banking inquiry.
Susan O'Keeffe and Michael D'Arcy joined last week in a move which ensured a majority on the committee for the Coalition.
Independent TD Stephen Donnelly stepped down at the weekend in reaction to the development.
A Government spokesperson has confirmed that no whips will be imposed on party members serving on the inquiry.
However Sinn Féin's Finance spokesperson Pearse Doherty says it must go back to being a nine-member team.
"I think what really needs to be done now is to go back to where we should have been, and that is with the nine members of the inquiry," he said.
"I think the easy thing and the easy way to resolve this overnight is for the two members to say: 'Look, we're not going to allow our names to be used in a way that could actually collapse a banking inquiry', and the best way to do that is to step aside."