A possible merger between the SDLP and Fianna Fail cannot be ruled out, Mark Durkan has said.
Mark Durkan said he would not rule out a merger
The SDLP leader was responding to Taoiseach Bertie Ahern who said his party is to organise in Northern Ireland for the first time.
Fianna Fail has set up a committee to implement the move. Mr Durkan said it was "a positive development".
"We now have the possibility of new alignment within northern politics and on a north-south basis," he said.
"We don't want to pursue either at the expense of the other, because both are part of the positive change of opening up the new political landscape."
It is the first time in Fianna Fail's 81-year history that efforts have been made to mobilise on an all-Ireland basis.
Mr Ahern said Foreign Affairs Minister Dermot Ahern would chair a committee to implement the move.
"This moves reflects the dramatic changes we have seen across the island," the party leader said.
Dermot Ahern said the party did not intend to contest any seats in a Westminster election.
"We wouldn't be interested in going to the House of Commons as a political party. That is for others to do," he said.
"We feel we should have representation in Northern Ireland as a political party."