Mr Hogan has strenuously denied allegations by Dublin MEP Nessa Childers that, when Environment Minister, he intervened in the allocation of social housing in Kilkenny. He says the allegations are now the subject of two High Court proceedings.
However, the issue has become one about freedom of expression following his issuing three lawyers’ letters to Ms Childers.
Some MEPs are seeing it as pressure on them before the hearing and want Parliament president Martin Schulz to take up the matter with Commission president, Jean Claude Juncker.
Mr Hogan’s spokesperson said he had no option but to defend himself and accused Ms Childers of misrepresenting the facts.
Ms Childers distributed a letter to 200 MEPs from the two main political groups in the European Parliament some weeks ago about the housing controversy.