The Irish Alliance for Europe, which was founded recently to campaign for a Yes vote in the Nice referendum, has rejected claims from the No lobby that it is a Fianna Fáil front organisation.
Mr Justin Barrett, of the No to Nice Campaign, had claimed that the alliance was "nothing more than a department of Fianna Fáil and its vaunted claims of political independence are totally unfounded".
He added: "Apart from a few figureheads, the so-called Alliance for Europe does not exist as a separate entity. It is Fianna Fáil in all but name."
He claimed that a named member of Ógra Fianna Fáil, the party's youth wing, was a member of the alliance, and had recently been appointed to a position in the Department of the Taoiseach.
He also claimed that Fianna Fáil was putting up posters for the alliance at the same time as its own pro-Nice posters. "More than one person, including myself, have seen the posters being erected around the country and they are being erected by the same people," Mr Barrett said.
However, a spokesman for Markon Enterprises, a Howth-based commercial firm which erects political posters on a fee basis, told The Irish Times last night that it had been hired "completely separately" by Fianna Fáil and the alliance to put up their posters. "They are separate payments and invoices."
The firm's general manager, Mr David Wright, said it was "fairly standard" to put up posters for different organisations at the same time, "rather than doing the runs twice". The firm had put up posters for different political parties in the general election. "It is a commercial operation."
The campaign director of the Alliance for Europe, Mr Adrian Langan, said he could provide documentary evidence that the organisation had contracted and was paying to have its own posters erected.
Mr Langan said: "This is an example of ludicrous muckspreading which has no place in this campaign."
He called on the No to Nice Campaign "to withdraw this allegation and to campaign on the issues".
Contrary to Mr Barrett's claims, Ms Averil Power, personal assistant in the Department of the Taoiseach to the Government chief whip, Ms Mary Hanafin, had never been a member of the alliance, Mr Langan said.
Ms Power herself told The Irish Times she had no connection with the alliance. She had been active with the pro-Nice youth group, Ireland for Europe, but this ceased when she took up her present position at the end of July, before the Alliance for Europe was founded.
The Fianna Fáil Minister of State for European Affairs, Mr Dick Roche, said Mr Barrett's claims of a party link with the alliance were "nonsense".
"It is just a device by the No to Nice Campaign to deflect attention from the fact that they have been guilty of putting up the most offensive and insensitive posters that the country has ever seen - the man with the gun to his head."