Irish Foreign Minister Simon Coveney said on Friday the prospect of Britain introducing laws to unilaterally overrule parts of the Northern Ireland protocol governing post-Brexit trade is causing friction in talks with the European Union.
Britain and the EU have spent months trying to agree on how to remove many of the checks on goods entering Northern Ireland from the rest of the UK agreed to under the protocol.
A British minister said on Thursday that the two sides were at an impasse.
Local media have reported that Britain is preparing laws that could be announced as soon as next month to do away with parts of the protocol. Ministers have said they are looking at a range of options.
“What we're hearing from some voices in London at the moment is that the British government is going to effectively pass domestic legislation to override elements of international law … in order to do away with elements of the protocol,” Mr Coveney said at an event in the US.
“That is causing tension between the British government and the EU.”
Perceptions that the protocol erodes Northern Ireland's place in the UK have sparked anger in pro-British communities.
The largest unionist party, the Democratic Unionist Party (DUP), has said it will not enter a new power-sharing government after elections next week in the British-run province unless the protocol is completely overhauled.
Mr Coveney said the DUP stance, along with anxiety in parts of the unionist community over polls showing Irish nationalists Sinn Fein set to become the biggest party for the first time, will make forming a new administration “very, very difficult".
He said the institutions established under the 1998 Good Friday Agreement were “perhaps under more threat now than they have been at any point” since then and added that he remained hopeful that Northern Ireland would find a way out of the impasse.
The Good Friday Agreement largely ended three decades of violence between mainly Catholic nationalists seeking to merge with Ireland and Protestant unionists who want to remain part of the UK.