The former SDLP leader, Mr John Hume, and his one-time deputy leader, Mr Seamus Mallon, have distanced themselves from a proposal to merge the party with Fianna Fáil.
A former vice-chairman of the SDLP, Mr Tom Kelly, wrote a comment piece in the Observer newspaper last month favouring a merger. Speaking as he and Mr Mallon were honoured in Waterford for their role in the Northern peace process, Mr Hume said: "I would take a view very strongly against Southern parties becoming all-Ireland parties and we doing the same in the North. It would never solve the Northern Ireland problem.
"Our correct approach to the problem, which underlines our reasons for going into politics in the first place, is to work with people and help them. This populist nonsense of getting parties in the South to become organised in the North and call themselves all-Ireland parties - to this my message is very clear, all political parties must act in the name of the people so let us act for the people rather than letting this become a party political issue."
Mr Mallon said: "I would welcome a debate on the issue. I would welcome the debate at a branch meeting, especially a meeting of the branch Mr Kelly belongs to, at one of our constituency council meetings, district executive meetings or executive meetings. Indeed, I would dearly welcome Mr Kelly's attendance at any such internal meeting."
Questioned about the growing electoral strength of Sinn Féin ahead of the Assembly elections in May, Mr Hume said he "believed strongly" that the suggestion of major seat losses by the SDLP was an "insult to the intelligence of the people of the North".
Mr Hume and Mr Mallon were guests of honour at a dinner attended by SDLP leader, Mr Mark Durkan MLA.