The DUP has been accused of “dropping the ball” by their unionist rivals in Northern Ireland.
Agreement was reached between the UK and EU on Thursday just weeks before Brexit.
The DUP said it is “unable” to back the proposals in the Commons as they are not in the best interests of Northern Ireland.
However Ulster Unionist peer Lord Empey was critical of the DUP, accusing the party of “opening the door to a regulatory border in the Irish Sea”.
“The lesson of this sorry state of affairs is that the Union is not safe in the DUP’s hands; they have dropped the ball,” he said.
“They have failed to ensure that the UK leaves the EU on time and have opened up a can of constitutional worms as well, because any future negotiations will use their proposed border in the Irish Sea concession as a starting point.”
TUV leader Jim Allister claimed the deal places Northern Ireland in a “waiting room for a united Ireland”.
“The inescapable reality is that a permanent regulatory and customs border cutting us off from GB puts us in a waiting room for Irish unity with the door locked from the outside,” he said.
“Subject to EU Single Market and Customs Union rules, over which we have no control, and crippled by tariffs on GB trade, we are removed into the economic orbit of the Republic with the purpose of ‘ever closer union’ ensuring the union slowly bleeds to death.”
Meanwhile, SDLP leader Colum Eastwood described the deal as “not ideal”, but voiced hope it would prevent a hard border in Ireland.
“The Brexit deal agreed this morning confirms our long-stated position that there is no such thing as a good Brexit – only degrees of harm caused to economic and political stability on this island,” he said.
“This deal does however meet the minimum requirements to avoid a hard border and the introduction of customs or regulatory checks across this island. That is welcome and EU negotiators have obviously worked very hard to defend our interests. If the choice is between this deal or no deal, then the interests of people here must be defended.”
The leader of the centralist Alliance Party has renewed her call for a People’s Vote.
Naomi Long said: “There is no such thing as a good or sensible Brexit, but we recognise no deal will be catastrophic for Northern Ireland in particular.
“Instead of the ‘easiest deal in history’, as sold by the Leave campaigns, we are now effectively being asked to choose between a poor deal and no deal, a rock and a hard place.
“People were promised unicorns in 2016, yet now they are now being asked to choose between a lame donkey and a dead donkey. Given the need to avoid no deal, our preference is Parliament passes the Johnson deal subject to it being put to the public in a UK referendum, with Remain on the ballot paper. Anything else is selling the electorate short.”
The leader of the Green Party in Northern Ireland Clare Bailey echoed the call for a People’s Vote.
“It’s clear that this latest deal should be put back to the people of the UK via a People’s Vote. Furthermore, the proposal around a vote in a defunct Stormont Assembly is paper thin. I’d rather see a say for the people of Northern Ireland as a whole,” she said.
“Let’s cut across the chaos at Westminster and inertia at Stormont and provide a say to the people who will be subject to this deal.”