SDLP leader Colum Eastwood and Fianna Fail leader speaking at Artola House last month
His Dublin speech is expected to focus on the parties’ joint Brexit strategy.
In January, Fianna Fáil and the SDLP announced the partnership arrangement but insisted they were not merging and would retain distinct identities.
The Foyle MLA said today will be an important step in a growing political relationship.
Earlier this week, Mr Eastwood and Fianna Fáil leader Micheál Martin issued a statement urging all pro-remain parties on the island to form an alliance.
Mr Eastwood said the Ard Fheis was an “important first outing” for the partnership.
He said Fianna Fáil and the SDLP were “very excited” about it.
“This is a long-term plan. It’s no quick fix, it’s not short term. It’s not about the next election, it’s about the next generation.”
“I’ll be speaking about Brexit, I’ll be speaking about the future of our country,” he said.
“I’ll be trying to remind people that, yes, we can all hold placards against Brexit, but there are certain places that we can go to, to actually stop it,” he added.
Referring to Sinn Féin’s policy of abstentionism at Westminster he added: “When Theresa May’s majority is disintegrating in front of our very eyes, it is crazy that we have seven MPs in the north, who won’t go, do their job and vote Brexit down”.
The UK is due to leave the European Union on 29 March.
Mr Eastwood also said that politicians needed to get “back round the table” to get Stormont back up and running.
