Northern Ireland's First Minister Michelle O'Neill welcomed news of a deal between the UK and EU but cautioned that the "devil will be in the detail".
Meanwhile, DUP leader Gavin Robinson said a deal that will see fewer checks on some goods coming from GB to NI will be assessed through "the prism of the union".
Speaking at Stormont, O'Neill acknowledged there had been an "improved relationship" between London and Brussels.
"Anything that protects the all-island economy, anything that maximises our access to both markets in terms of trade, anything that removes barriers for trade, then that's something that we would obviously very much welcome," she said.