Northern Ireland's political parties that take their seats at Westminster are set to vote against the UK-EU post-Brexit deal this week.
The Commons will be recalled on Wednesday to allow MPs to vote on the agreement reached on Christmas Eve.
The DUP, the Alliance Party and the SDLP have indicated that they will not support the plan.
It comes as the Stormont Executive met virtually to discuss the deal in detail for the first time.
The DUP's Brexit spokesman Sammy Wilson told BBC Newsline that because the agreement did not address "many issues that are damaging to Northern Ireland" his party's eight MPs would vote against it.
'Kicked down the road'
Prime Minister Boris Johnson has a large majority of Conservative MPs and Labour has said it will also whip its MPs to support the plan.
But Mr Wilson said that was no reason for the DUP not to "articulate concerns people in Northern Ireland have about the deal".
"Many things have been left unaddressed and kicked down the road... we'll be saying to the government that these are still issues which we believe are resolvable," he said.
"We expect you [the government] to fulfil promises you've made to the people of Northern Ireland but you haven't done it to date, so don't expect our support."
The DUP said it would vote against the deal "as a point of principle and not because we supported a no deal option".
"A free trade deal is better than no deal but for Northern Ireland this deal does not undo the detrimental aspects of the [Northern Ireland] Protocol," added the party.
The DUP's Westminster team will meet on Tuesday for further discussions.
Sinn Féin has seven MPs but its party does not sit in Westminster due to its long-standing policy of abstentionism.
EU ambassadors have approved the post-Brexit trade deal, paving the way for it to take effect on 1 January.
Under EU rules it can take effect provisionally, though the European Parliament will vote on it in January.
'Reaffirm our opposition'
The Stormont assembly will return early from Christmas recess on Wednesday to debate the trade deal.
The speaker confirmed it in a letter to MLAs on Monday night after a request from the first and deputy first ministers.
MLAs will debate a motion that "takes note" of the deal reached by the UK and EU last week, but it will not be legally binding.
John O'Dowd, Sinn Féin's chief whip at Stormont, said it was important the assembly was recalled to "reaffirm our opposition to Brexit and reiterate our call for the full implementation" of the withdrawal agreement and Northern Ireland Protocol.
He said that as political institutions in other parts of the UK were returning from Christmas break early to discuss the deal it was important that the Stormont assembly also did so.
"We think it's vitally important that the voices of workers, businesses and families in the area most affected by Brexit is heard," he added.
'Range of uncertainty'
Alliance Party MP Stephen Farry said he had concerns that the legislation relating to the deal had yet to be published ahead of the vote.
"That's another reason for being sceptical about giving a blank cheque to the government around this - it's coming at the eleventh hour.
"I'm certainly not going to be there as a rubber stamp to just blindly wave this through when the bill hasn't even been published yet."
SDLP MLA Matthew O'Toole said his party would not endorse the deal.
"There is a whole range of areas where we don't have certainty about what is going to happen in the future," he said.
"It's the biggest creation of trade barriers in modern history - this is unique, it is putting up barriers between businesses and people."
'Minimal say in bureaucratic systems'
Ulster Unionist leader Steve Aiken said the trade deal was "better than no deal but this is only because it was the least-worst option".
"Many non-tariff barriers have now been created and we have been inflicted with the protocol, meaning that Northern Ireland will have to deal with the consequences of two bureaucratic systems," he said.
"We will have a minimal say in one and none in the other."
The assembly voted this year to support withholding consent for the UK's withdrawal from the EU and in favour of extending the transition period.
Sinn Féin, the SDLP, the Alliance Party and the NI Greens oppose Brexit, while the DUP and TUV supported Brexit but rejected the withdrawal agreement reached last year.
The Ulster Unionists campaigned against Brexit but later accepted the referendum result, however the party also opposed the Northern Ireland Protocol, the special part of the withdrawal agreement relating specifically to Northern Ireland.
The unionist parties argue that the creation of an Irish Sea border through the deal poses a risk to the future of the union.