Fianna Fáil is insisting that it did not expel Brian Crowley - but rather that he effectively ousted himself from the party fold.
The Ireland-South MEP has aligned himself with a Eurosceptic political grouping at the European Parliament, departing from the more liberal alliance to which Fianna Fáil is affiliated.
He lost the whip at a meeting of the parliamentary party today.
But Senator and Fianna Fáil Party Whip Sean O'Fearghail is denying Brian Crowley was booted out:
It is understood that the party considered Mr. Crowley to have removed himself from the parliamentary party, when he left Fianna Fáil's liberal European grouping - ALDE - to join the Eurosceptic ECR group.
In a statement, Fianna Fáil Chairman Brendan Smith and Whip Seán Ó Fearghaíl said "At today's meeting of the Fianna Fáil Parliamentary Party, it was agreed that the ideas and principles of the ECR group and its component parties are totally incompatible with the core principles of Fianna Fáil".
Senator and Fianna Fáil Party Whip Sean O'Fearghail is denying Brian Crowley was booted out.
Mr. Crowley had said it was because the ECR is a "non-federalist, pro-EU group" that wants national governments to have more power. He also maintains the move will help save the jobs of his Irish staff, who could be laid off otherwise.
But Fianna Fáil says his staff would have kept their jobs. The party had said it is unacceptable for someone who ran under the Fianna Fáil banner last month to join a group whose principles openly conflict with its own.
Several members of the parliamentary party believe no action should have been taken against Mr. Crowley, before he was allowed to address the group. Senator Mark Daly said it was important that the Ireland South MEP provide an explanation for events and objected to Mr. Crowley being expelled.
Fianna Fáil TD John Browne says he believes Mr. Crowley should have been allowed to address its parliamentary party.
Deputy Browne was one of a number of members of the parliamentary party that had requested that Mr. Crowley be allowed to address them as to his reasons for leaving the ALDE group.
He spoke to Southeast Radio:
