Senator Callely has been suspended from the Fianna Fáil organisation over new expense allegations and pending the completion of an internal investigation.
The Fianna Fáil party has said it has reviewed certain matters in the public domain concerning Ivor Callely and have said that the information establishes a possible prima facie case of conduct unbecoming to a member of the Fianna Fáil organisation.
The party will establish an internal investigation into the matter which will report to the Fianna Fáil Ard Chomhairle in September.
Pressure had been growing on Senator Ivor Callely to refute new expenses allegations or to resign from the Seanad.
It emerged in an article in the Irish Mail on Sunday last week that there were new expense allegations relating to receipts for mobile phone equipment, from a company that had ceased trading.
Mr Callely was suspended from the Seanad for 20 days last month following an investigation into expense claims he made from a home in West Cork while maintaining a house in Dublin.
Fianna Fáil members have called on the Senator to clarify his position.
Opposition parties and other senators are calling for gardaí to investigate the latest allegations concerning Ivor Callely.
Ivor Callely has made no comment about these latest allegations.