Deputy First Minister Martin McGuinness says he has “no faith” that Parliament would vote to reject the Brexit process being triggered following Thursday's ruling at London's High Court.
Three senior judges ruled that Prime Minister Theresa May does not have power to use the royal prerogative to trigger Article 50 of the Lisbon Treaty without the prior authority of Parliament.
However speaking at Stormont Castle, Mr McGuinness was not encouraged by the judgement.
“I think we will all obviously have to await what happens in the time ahead and deal with that and that’s precisely what we’ll do,” the Sinn Féin MLA said.
“We’re opposed to Brexit and we believe that any decision about the future of the people of this island need to be taken between our administration in the north and the government in Dublin.”
DUP East Belfast MP Gavin Robinson has said if MPs used a vote to thwart the outcome of the referendum, it would be “politically explosive.”
“I do believe it would encourage the Prime Minister to go back to the people in an early election,” he said.
DUP deputy leader and MP Nigel Dodds said he was disappointed by the ruling and that the democratic vote must be respected.
“On 23 June, the British people as a whole gave a clear mandate for the UK government to leave the EU,” he said.
“There must be no attempt to block Brexit by people who refuse to accept the will of the people of the UK.”
Mr Dodds added: “Her Majesty’s government will be appealing the decision and I am aware this will be in the beginning of December.”
An Ulster Unionist Party spokesperson said their MPs would vote to trigger Article 50.
“We will study the detail of this judgement. We are very aware that the Government will appeal this decision in the Supreme Court and we will wait for the outcome of that," a statement said.
“Parliament voted to give the people of the United Kingdom the opportunity to vote in a straight in/out referendum.
"On 23 June, the people of the United Kingdom voted to leave the European Union and, on that basis, should the appeal be unsuccessful, our MPs will vote to trigger Article 50.”
Alliance Brexit spokesperson Stephen Farry MLA has welcomed the High Court ruling.
“This at least now provides an opportunity for Parliamentary and Assembly scrutiny of the issues around Brexit,” he said.
“This judgement is obviously going to be appealed by the Government. Notwithstanding the final outcome, it is clear they now need to spell out much more clearly what they intend Brexit to mean."
He added: “In the event the Supreme Court rules there is indeed a vote required, it raises the issue of the need for a legislative consent motion in the devolved assemblies.
"It is now vital the Executive takes its own legal advice on this as a matter of urgency.
“Ultimately, Brexit has such fundamental implications for the UK and Northern Ireland, it would be perverse if decisions regarding the formal triggering of Article 50 were not subject to the most detailed scrutiny and accountability.”
SDLP Foyle MP and member of the Westminster Brexit Committee Mark Durkan also welcomed the ruling.
“I have consistently called on the government not to begin the formal process of triggering Article 50 on withdrawal from the EU until its proposals have been fully considered in the House of Commons and voted upon by MPs.
“Parliament has the right and the duty to ensure that we best consider how these matters are dealt with.
“However, the idea seemed to be that Parliament had no role whatsoever, and could entrust these matters entirely to the royal prerogative and those who are meant to be leading the process. That would constitute a request for us to commit a dereliction of duty.”