A bill to unilaterally amend the Northern Ireland Protocol will be introduced in Parliament on Monday amid controversy over whether the legislation will break international law.
Northern Ireland Secretary Brandon Lewis has insisted the new Bill is "lawful" and "correct" but Labour has accused the Government of "law-breaking".
The legislation will give ministers powers to override elements of the protocol, which was jointly agreed by the UK and EU as part of the Brexit Withdrawal Agreement to keep the Irish land border free-flowing.
The arrangements instead require regulatory checks and customs declarations on goods moving between Great Britain and Northern Ireland.
Unionists in Northern Ireland are vociferously opposed to the international treaty, claiming it has undermined the region's place within the United Kingdom.
The DUP has blocked the formation of a new power-sharing government at Stormont following last month's Assembly election in protest.
There is also likely to be some opposition to the bill from within Tory ranks, with a number of MPs believed to be unhappy with the legislation.
The Financial Times reported that an internal note had been circulating among those against the Bill, which said: "Breaking international law to rip up the Prime Minister's own treaty is damaging to everything the UK and Conservatives stand for."
The Bill due to come before Parliament will see the Government move without the consent of the EU to change the terms of the protocol in a bid to reduce the checks on the movement of goods across the Irish Sea.
This could include allowing ministers to remove all customs processes for goods moving within the United Kingdom and enable the frictionless movement of agri-food goods staying within the UK.
It could also see businesses in Northern Ireland given the ability to choose whether to follow UK or EU regulations, depending on who they are trading with.
The EU has made clear that such steps would represent a breach of international law and could prompt retaliatory action from the bloc.
Mr Lewis has said he hopes the Bill will persuade the DUP to support the re-establishment of the Stormont institutions.
He has also said the Government will set out its legal position on the Bill when the legislation is introduced to Parliament on Monday.