Northern Ireland's parties united in opposition to backstop assurances
The DUP has rejected the Prime Minister's latest assurances on the backstop as "cosmetic and meaningless".
The party remains set to vote against the Withdrawal Agreement in the House of Commons on Tuesday.
Sinn Fein also dismissed the proposal to give the Assembly a "strong role" if the backstop is triggered, claiming this would hand "a veto" to the DUP.
- The pledges in Government’s white paper that were universally dismissed
- UK Government commitments to Northern Ireland and its place in UK [Full document]
In a 13-page paper published yesterday, the Government pledged to enact new domestic laws to quell fears that Northern Ireland would be treated differently from the rest of the UK if the backstop came into play.
If the backstop is triggered, the Government vowed that the Stormont Assembly and Executive would be given a "strong" oversight role in its operation.
But DUP deputy leader Nigel Dodds said these commitments had not changed his party's opposition to the Brexit deal, because any amendments to British domestic law would be trumped by the provisions of the Withdrawal Agreement.
"We reject the backstop and have previously, and consistently, indicated we will not support an internationally legally binding withdrawal agreement that contains its provisions," he said.
"Such an international treaty supersedes and overrides any contrary domestic legal provisions.
"The Assembly would not be able to override UK international legal obligations, as the backstop provisions would be in the treaty."
Sinn Fein president Mary Lou McDonald said the Withdrawal Agreement and the backstop were "the least worst options in the disaster that is Brexit".
She continued: "These cannot, and will not, be rewritten, renegotiated or vetoed by Westminster or the Assembly.
"Furthermore, no British government can unilaterally limit the role and function of the North South Ministerial Council or rewrite the Good Friday and other agreements.
"We are seeking an urgent meeting with the British Prime Minster on these matters."
UUP leader Robin Swann said: "The document published by the UK Government is frankly insulting.
"Its only purpose seems to be to state what we already know, rather than going any way towards addressing the very real concerns we have repeatedly outlined to Government ministers and officials."
UUP MEP Jim Nicholson also dismissed the paper. "These proposals fall well short of what is necessary, which is change to the legally binding text of the Withdrawal Agreement," he said.
"Up against a legally binding international treaty, this so-called veto is merely window dressing and frankly toothless."
SDLP leader Colum Eastwood said the proposals were "nothing more than an empty veto being handed to an empty chamber - an attempt, no doubt, to appease the DUP and a tactic that has once again failed."
SDLP MLA Claire Hanna described the Government's pledge to offer Northern Ireland an opportunity to provide consultative advice on the backstop as "unconstructive ambiguity".
She said: "On the two-year anniversary of the collapse of power-sharing, the British Government is proposing to transfer ambiguous decision-making powers to the Northern Ireland Assembly at a time when no decisions can be taken."
Alliance deputy leader Stephen Farry dismissed the contents of the Government's paper as "spin".
He claimed the Assembly should not have a veto over the introduction of the backstop, which was a matter for London and Brussels.
Dr Farry said the Stormont institutions may still be moth-balled and, even if they weren't, there was the "risk of political games being played by the DUP inside the Executive and abuse of the petition of concern on the floor of the Assembly".
Green leader Clare Bailey branded the Government's proposals "pie-in-the-sky politics".
She said: "Perhaps the Secretary of State, Karen Bradley, can inform her Prime Minister that the Assembly and Executive don't operate at present.
"This pie-in-the-sky proposal shows the Tory Party has no real interest in restoring devolution here or protecting us from Brexit."