Ms Patricia McKenna, a Green MEP, attended the recent EU summit in Greece as a "journalist" with the Socialist Worker newspaper, which is published by the Socialist Workers Party.
Ms McKenna said last night that she had used the accreditation to gain access to the summit because MEPs are not allowed to attend such meetings.
Earlier, the Department of Foreign Affairs confirmed that Ms McKenna's name and accreditation for the summit with the Socialist Worker was on a list provided to the Irish embassy in Greece.
Ms McKenna said she approached the Socialist Worker with a view to writing an article for it about the summit, which took place almost a fortnight ago. However, she had not yet submitted an article and believed that the paper might conduct an interview with her instead.
Ms McKenna said "not really" when asked if there could have been any conflict of interest in a full-time elected representative of the Green Party attending such a summit as a journalist for a paper published by a rival political party. She said she wanted to attend the summit to inform herself about the development of a common EU foreign policy. She chose to approach the Socialist Worker because the Greens had no newspaper.
Ms McKenna said she never sought formal permission from her party to attend the Greek summit in this way.
However, she said she had mentioned it in a casual way to some party colleagues. "There was no permission sought, or given, or denied," she said. "For me, there was never anything in it that I needed permission for."
The leader of the Greens, Mr Trevor Sargent, did not respond last night to questions from The Irish Times about Ms McKenna's attendance at the summit.
However, the party's foreign affairs spokesman, Mr John Gormley, said he had no personal difficulty with Ms McKenna's means of attending the summit. "I don't think there'd be much of a problem actually. It was probably the only way of getting into the summit." While he accepted the Greens had "major differences of opinion" with the Socialist Workers Party on some policies, Mr Gormley said the party was not a "total rival" to the Greens and noted their joint opposition to the war in Iraq.
The Socialist Workers Party is a revolutionary socialist party. Its website promotes a form of socialism which it says must come from the self-emancipation of workers.
Ms McKenna said she had no plans to join the party. She said she had attended the EU summit in Seville last year as a journalist accredited to a Danish newspaper whose editorial stance was critical of the EU.