Construction of permanent facilities to check goods arriving to Northern Ireland from Britain under post-Brexit arrangements have been halted over concerns about the new rules, a minister said on Friday.
Northern Ireland Agriculture Minister Gordon Lyons said he had stopped construction of the inspection posts at ports amid disagreements over the implementation of a post-Brexit trade protocol.
Mr Lyons said his move was in response to "practical difficulties" caused by the protocol, citing uncertainty over the movement of goods when arrangements come into full effect at the start of April.
"We don't know what the movement of retail goods from Great Britain into Northern Ireland is going to look like," said Mr Lyons, from the pro-UK Democratic Unionist Party.
"It's real nightmare for us and it's going to be causing us an awful lot of problems."
Since the Brexit transition period ended on January 1, a special set of arrangements has governed trade in the British province of Northern Ireland, which is home to 1.9 million people.
Under a divorce deal agreed between Brussels and London, Northern Ireland has effectively stayed in the EU customs union and single market for goods, with checks on freight arriving from mainland Britain.
The move was designed to prevent hard infrastructure on the border with EU state Ireland to the south – a flashpoint in sectarian conflict that ended in 1998.
But the Northern Ireland Protocol has caused anger, particularly in the pro-British unionist community.
The Democratic Unionist party filed a legal bid earlier this month to scrap the protocol after it disrupted trade and triggered some food shortages.
The British government and the European Commission have said they will "spare no effort" to uphold peace in Northern Ireland.
Fears of sectarian tension in Northern Ireland were fuelled after the European Commission said it would restrict Covid-19 vaccine exports as the bloc struggles with its own supply.
Although the EU quickly backtracked, the abortive move has intensified opposition to the new regulations, and threats against officials forced the temporary suspension of customs checks at two ports in Northern Ireland this month.