SDLP leader Margaret Ritchie claimed votes from across the community helped secure her a landslide win in South Down.
Ms Ritchie clinched 20,648 votes - 8,412 more than her closest rival, Sinn Fein Education Minister Catriona Ruane, allowing her to retain the seat vacated by her political mentor Eddie McGrady.
Ms Ritchie said she did not expect to win by such a majority, but would not be drawn on a Sinn Fein claim that the victory came from tactical voting by unionists.
"I don't want to go down the road of trying to syphon off or suggest where votes came from. Votes came from right across the community, I welcome that," Ms Ritchie said.
"That's for the sound representation and the sound policies provided by the SDLP."
Ms Ritchie said she would be giving consideration to stepping down as Minister for Social Development over the coming days.
"I will be appointing one of my colleagues to that position," she said.
The retirement of veteran MP Mr McGrady made this a competitive seat for Sinn Fein, who were just 328 votes behind the SDLP in the 2007 Assembly election.
Mr McGrady secured 21,557 votes in the 2005 Westminster election, followed by Ms Ruane with 12,417.
Ms Ruane said she was pleased her percentage vote had increased from the 2005 vote, but blamed her loss on an "anyone but Sinn Fein" vote.
"It's obvious to everybody what happened here. The TUV, the DUP and the UUP voters voted with the SDLP tactically," Ms Ruane said.
"Our work continues in this constituency, our vote increased, the percentage of it increased, I welcome that and we're going to continue building. Looking forward to the Assembly election next year."
The total results for South Down were Cadogen Enright (Green) 901, David Griffin (Alliance) 560, John McCallister (UCUNF) 3,093, Ivor McConnell (TUV) 1,506, Margaret Ritchie (SDLP) 20,648, Caitriona Ruane (Sinn Fein) 12,236 and Jim Wells (DUP) 3,645.