Contrary to Labour's stated policy on Ireland's participation in Partnership for Peace, the party's new foreign affairs spokesman, Mr Proinsias De Rossa, has said he intends to make "a particular case against joining".
Immediately after the announcement of Labour's new front bench yesterday, Mr De Rossa confirmed that he would "press that Ireland should not join Partnership for Peace".
"It would be a major step towards joining NATO," he said.
As a result of the decision of the former Labour leader, Mr Dick Spring, not to take any portfolio in the new line-up, the foreign affairs brief that he held since stepping down has fallen to the party's new president and former Democratic Left leader.
Labour's 1997 general election manifesto states that "it could be a legitimate and proper role for Ireland to participate, in due course, in the pan-European structure of the Partnership for Peace".
"This has already been joined by other European neutral states, such as Switzerland, Austria, Finland and Sweden.
"The Partnership for Peace is not a military alliance. Ireland would be free like all other countries to negotiate its own terms," the manifesto added.
However, Mr De Rossa said he intends to "make a particular case against joining".
"I am a democrat. The party will make a decision and I will abide by that. I hope it is in favour of my view," he added.
Having discussed the matter with senior figures in the Labour party, he did "not forsee foresee difficulties".
Insisting the divergence in opinion on this issue would not create any internal tensions, a Labour spokesman said "if Ruairi Quinn and Proinsias De Rossa have managed to get this far in terms of the whole merger and all the difficulties associated with that, this [Partnership for Peace] is the least of our problems".
The Dail, meanwhile, is scheduled to debate a Fine Gael motion urging Ireland's participation in Partnership for Peace when the House resumes tomorrow after the Christmas recess.