Fianna Fáil and Northern Ireland's SDLP have issued a joint statement, calling on pro-remain parties across Ireland to form a Brexit alliance.
The statement was issued by party leaders Micheal Martin and Colum Eastwood.
It has set out five core principles for parties across the island to agree on over Brexit.
"The arithmetic in Westminster no longer allows us to leave anything to chance", the statement said.
"Brexit can only be stopped by actions, not words or placards.
"Extraordinary times call for more than ordinary measures.
"Together, pro-remain parties must agree and act upon a set of principles that ensure the protection of people across this island, from Derry to Cork.
"Together, the SDLP and Fianna Fáil agree that all pro-remain parties must recognise and invoke five core principles necessary to stave off the worst outcomes of Brexit".
The principles include forming the joint alliance, with the restoration of the Stormont executive, standing firm on the Irish border backstop and voting down any no-deal Brexit.
"The key to forming a pro-remain alliance worthy of more than joint press statements lies in the restoration of Stormont.
"An executive is vital if we are truly to protect our economy, farms and businesses from the fall-out of Brexit."
"It is simply not enough to oppose a no-deal Brexit - it must be voted down", the statement added.
"All pro-remain parties have a duty, whether it be in the (Stormont) Assembly, the Dáil or in Westminster to make every vote count".
It also has called for recognition that both unionists and nationalists voted to remain.
"Pro-remain parties must recommit to reconciliation.
"We must work to ensure that peace, through the spirit that delivered the Good Friday Agreement, is a priority we never let slip".
The release is one of the first statements sent from the parties on a joint basis since they announced their partnership in late January.
Mr Eastwood is also set to attend the Fianna Fáil Ard Fheis at Dublin's Citywest Hotel on Saturday.