Irish government party Fianna Fáil is to consider a proposal to formally end its partnership with the SDLP.
The two parties announced a cross-border alliance in 2019 but the status of the collaboration since then has been uncertain.
Fianna Fáil's youth wing passed a motion at its conference in Co Donegal at the weekend calling for an end to the partnership.
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The motion asked the president of Ógra Fianna Fáil to take the proposal to the party's ruling body.
It read: "This conference calls for an end to the SDLP-Fianna Fáil partnership and mandates the incoming president to propose a motion to this effect at the next Ard Comhairle meeting."
The motion, which was put forward by Kildare North members, is understood to have passed by 20 votes to 14.
It follows claims of tensions between the two parties' youth wings in the years since the partnership.
The proposal emerges just days after Taoiseach and Fianna Fáil leader Micheál Martin met with SDLP leader Colum Eastwood during a visit to Derry.
Mr Eastwood has previously praised the partnership, arguing that it played a role in the Irish government setting up the multi-million-euro Shared Island Unit to boost north-south cooperation.
"This has been a policy partnership that has been about trying to change people's lives," he said last month.
"And let me give you the evidence of what has happened as a result of that. There's one billion euro in a bank account in Dublin to be spent by the Shared Island Unit.
"That was done as a result of the conversations I had with Micheál Martin. And if that is the result of that partnership, I'd be pretty happy."
But Mr Eastwood insisted that while his party has a "strong" relationship with Fianna Fáil, it also benefits from support from across the political divide in the Republic.
The SDLP and Fianna Fáil's "all-island partnership" was originally pitched as focusing on addressing Brexit and restoring devolved government at Stormont after the RHI scandal.
The parties also aimed to work together to "provide enhanced research, electoral and organisational capacity".
But little has been seen of the partnership in the years that followed.
Party sources view calls to end the collaboration as unwelcome timing for the SDLP during the current Assembly election campaign.
They believe the proposal could eventually be referred to the wider Fianna Fáil membership at its next annual conference.
Some Fianna Fáil politicians, such as TD Jim O'Callaghan, plan to help the SDLP with campaigning ahead of the Stormont poll in May.
However, the SDLP has also had support on the doors from representatives of other parties in the Irish Republic.
Fine Gael TD Neale Richmond has been out canvassing for SDLP candidates in the South Belfast and Strangford constituencies.
Fianna Fáil has been approached for comment.
An SDLP spokesman said: "The policy partnership between the SDLP and Fianna Fáil was always about cooperation that delivered meaningful change for people in communities across the island.
"The Shared Island Unit in the Department of the Taoiseach is one example of how our parties have shaped over €1billion of investment in border communities that will deliver tangible results for people.
"Only this week SDLP leader Colum Eastwood and Taoiseach Micheál Martin met in Derry to discuss projects that will enhance the lives of people living in the North West and across Ireland."
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