An anonymous blog which strongly criticised a sitting Sinn Féin TD was investigated as part of a review which led to one councillor being expelled from the party and another suspended for one year.
The party's ardchomhairle agreed on Sunday to expel Kieran McCarthy and suspend Melissa Mullane, both Cork county councillors, but Sinn Féin is refusing to outline the circumstances behind the move.
The incident has caused some surprise in political circles because of Sinn Féin’s usually strict internal discipline.
Mr McCarthy, based in Cobh, said he had been provided with no proper explanation for his expulsion and claimed problems had arisen when he and Ms Mullane expressed an interest in standing at the next general election.
The sitting Sinn Féin TD in their constituency is Cork East’s Sandra McLellan, who declined to comment.
Ms Mullane did not return calls.
Mr McCarthy said Sinn Féin had initiated a review because of allegations made and rivalries in the constituency, with the local organisation stood down a number of months ago.
Party sources said a blog called “An Rebel Óg”, which criticised Ms McLellan and the party generally, was included in the review.
Mr McCarthy said he did not know who was behind the blog and added there had been allegations of loans being misappropriated in an attempt to damage certain people, but insisted these had not been proved.
He accused senior figures in Sinn Féin of operating a "Spanish inquisition" style system and attempting a "poor effort at copying the way Fianna Fáil operates".
He also said the party had stabbed him in the back and attempted to "override the democratic process and stifle the will of [the] Sinn Féin membership in Cork East, who clearly had lost the confidence of the sitting TD".
A party spokesman said both Mr McCarthy and Ms Mullane had 21 days to appeal the decision of the ardchomhairle.
Mr McCarthy had not been given a copy of the constituency review nor provided with an adequate explanation for his expulsion, he said.
He added that he had been informed of his expulsion in person by a party official.
He also said he might run as an Independent candidate in the general election.
Sinn Féin won 10 seats on Cork County Council in last year’s local elections but with the expulsion of Mr McCarthy and the suspension of Ms Mullane, the party is down to eight.