SDLP MLA Claire Hanna says she remains opposed to her party's new partnership with Fianna Fail despite being selected as its Westminster candidate.
She resigned the party whip and stepped down as its Brexit spokesperson after the link-up.
In February, Ms Hanna said she "remained unconvinced" that an exclusive partnership with Fianna Fail was "the right vehicle with which to deliver the non-sectarian, transparent and social democratic new Ireland I believe in".
Writing in today's Belfast Telegraph, she acknowledges that her decision to run as the SDLP's Westminster candidate in South Belfast has "raised questions" about her view on the new partnership with Fianna Fail.
"The truth is that my views on this issue remain unchanged, although of course I remain a party member and SDLP MLA, including campaigning extensively in May's election," she says. "I still believe in maintaining good relationships with all parties in Ireland who are committed to democratic and peaceful means, and indeed further afield through the Party of European Socialists.
"However, sometimes some things are more important than party politics.
"On some occasions, we stretch ourselves beyond our own parameters for something more important. For me, this election is one of those times."
Ms Hanna says that South Belfast people deserve "to have their voice properly represented" in Westminster.
"The forthcoming general election is our chance to choose a different direction at this generational crossroads. It's a decision that transcends party politics," she writes.
"It's not about 'Orange', 'Green' or 'Other'. It's not about accusing each other of sectarianism, it's not about the Union, and it's not about a border poll. It's about the chance to address the threat that impacts us all - our economy, our jobs, our NHS, our environment, our agri-food sector - and this is much bigger than any party or ideology."