British politicians will next week debate a motion to approve measures needed to implement the Stormont brake in the Windsor Framework.
House of Commons leader Penny Mordaunt said the legislation relating to the brake will be published on Monday.
It enables the UK to stop new European Union laws from applying to goods in Northern Ireland if requested by at least 30 members from two parties of the Stormont Assembly.
British Prime Minister Rishi Sunak and European Commission President Ursula von der Leyen announced the new framework last month to replace the Northern Ireland Protocol which had led the DUP to collapse the Stormont power-sharing institutions.
DUP leader Jeffrey Donaldson voiced his strongest concerns to date over the UK-EU deal, saying his party was seeking changes from the British government.
Northern Ireland Secretary Chris Heaton-Harris said he had been encouraged by the reaction in the United States to the Windsor Framework.
The debate on Wednesday is expected to be followed by a vote on measures to implement the brake.
The opposition Labour Party has said it supported the deal overall, so those measures are likely to pass comfortably.
However, the debate will provide the first tangible test of sentiment among the DUP and also within Mr Sunak's own Conservative Party.
The US and UK governments share a desire to see strong, devolved government restored in Northern Ireland. In resolving the issues created by the Protocol, the Windsor Framework deal is good for NI and I'm encouraged by the positive reaction to the deal here in the US. (2/2)— Chris Heaton-Harris MP (@chhcalling) March 16, 2023
The prime minister's spokesman said that while the legislation would not be amendable by MPs, the government remained open to speaking to the DUP and others on any questions they may have.
"There are elements of how the framework is enacted which we do want to discuss extensively with the DUP, particularly around the Stormont brake and how that works in practice.
"They will be an important part of that, as will the other political parties."
The spokesman confirmed that more legislation would be required to implement other parts of the framework which would also require the backing of parliament.
In the Commons, DUP MP Sammy Wilson said ministers needed to explain the "difference between the rhetoric and the reality" of the framework document in Wednesday’s debate.
"There’s still 300 areas of EU law that will still apply to Northern Ireland even after the Windsor Framework, and the ECJ (European Court of Justice) will still adjudicate on them," he said.
Meanwhile, European Research Group (ERG) chair Mark Francois said it was sill awaiting the verdict of its so-called star chamber of legal experts.
"We now hope to see this completed before next Wednesday and members of the group will no doubt pay close attention to the star chamber’s conclusions, prior to any vote," he said.
The ERG is made up of Eurosceptic Conservative Party MPs.
The Taoiseach said he believes the Windsor Framework will be endorsed in the House of Commons by a "very large majority".
Speaking in Washington, Leo Varadkar said he did not intend to put pressure on the DUP to back the deal as he believed such an intervention "wouldn't be helpful".
"From my conversations with Prime Minister Sunak and also with Keir Starmer, the leader of the Labour Party, I would expect that it will pass and pass by a very large majority because there is support, not just from the Conservative Party for this but also from the other parties in the House of Commons," he said.
Asked for his view on the timing of next week's vote on the framework's Stormont brake mechanism, the Taoiseach added: "The decision on when to have a vote is a decision for the prime minister and the British government.
"We'll be having a European Council meeting next week, next Thursday and Friday. So that's when we will discuss it as EU prime ministers.
"So, you know, I suppose those dates were coming sooner or later, but ultimately, it's a call for the British prime minister rather than for me and I imagine he feels that he has very strong support for it, not just from his own party, but actually cross-party support from Labour and others."
Additional reporting PA