More than 100 public figures from business, politics and the arts have signed a petition calling on Fianna Fail to honour its pre-election pledge not to allow Ireland join the NATO-sponsored Partnership for Peace without holding a referendum.
Among the signatories is Mr Chris Andrews, son of the Dublin MEP Mr Niall Andrews and a Fianna Fail candidate in the coming local elections. His uncle is the Minister for Foreign Affairs, Mr David Andrews.
The Fine Gael MEP Ms Mary Banotti has already broken party ranks by calling for a delay in the Government decision to allow for public debate.
The Labour Party leader, Mr Ruairi Quinn, and its foreign affairs spokesman, Mr Proinsias De Rossa, have differed on the issue.
Other signatories of the petition range from the former UN deputy secretary-general, Mr Denis Halliday, to the Bishop of Killaloe, Dr Willie Walsh, and the celebrity chef Darina Allen to the Mayo footballer Willie Joe Padden. Artists and musicians are strongly represented on the list, among them Seamus Heaney, Brian Friel, Ronnie Drew and Christy Moore.