Fianna Fáil has tonight suspended Senator Ivor Callely from the organisation pending an internal investigation into his expense claims.
The party said it had reviewed "certain matters in the public domain concerning Senator Callely" and "agreed that this information establishes a possible prima facie case of conduct unbecoming a member of the Fianna Fáil organisation".
Mr Callely, who resigned the Fianna Fáil whip in June, claimed almost €3,000 from the Oireachtas for the purchase of mobile phones and related services from a company which Companies Registration Office records show ceased trading years earlier.
He was last month deemed to have misrepresented his normal place of residence for the purposes of claiming expenses by the Committee on Members' Interests of Seanad Éireann.
The committee's report said Mr Callely should be suspended from the service of the Seanad for 20 days and have his salary withheld because the misrepresentation was done "intentionally and was of a grave nature".
Mr Callely said he "strenuously" rejected the report's findings.
A Fianna Fail statement tonight said the party would establish an internal investigation into and that it would report to the next meeting of the party's Ard Chomhairle, which is scheduled for September.
"We have today written to Senator Callely and the Oscar Traynor cumann, Dublin North Central, to inform them of this matter," it said. Fianna Fáil said the decision was without prejudice.
Ógra Fianna Fáil, the party's youth wing, said it will move a motion calling for the expulsion of Mr Callely from the party at the next meeting of the Árd Chomhairle.
"Mr Callely has a responsibility to clear up a scandal which he alone created and one which has dragged
down the reputation of politicians ever further," it said.
Earlier today, Green Party TD Paul Gogarty and Independent Senator David Norris joined calls for the resignation of Mr Callely following the controversy about his expenses claims.
Mr Norris said it was not in his nature to "gloat" in relation to others’ misfortune or tragedy. But this was "a tragedy brought upon himself by Ivor Callely".
“It is now at the point where I think a whole series of principles have been violated.
“If the newspaper reports are true, and one assumes they must be. Then we are involved in what looks certainly like matters that require the attention of the police.”
Separately, Mr Gogarty said he had written to the clerk of the Seanad to make a formal complaint about Mr Callely's conduct.He said Mr Callely should "take the honourable decision and step down" until any questions regarding his expenses were answered.
Mr Gogarty said other people in a similar position would have "stepped down straight away", citing former junior Green Party minister Trevor Sargent, and former minister for defence Willie O'Dea.
Former minister Mary O’Rourke said Mr Callely had brought “shame and disgrace” on Fianna Fáil and should be expelled from the party.
Green Party chairman Dan Boyle, who is deputy leader of the Seanad and a member of the committee that ruled against Mr Callely in a recent travel expenses investigation, said he could not be removed from office. Mr Boyle called on Mr Callely to consider his position at the weekend.