The European Union is "strongly concerned" the UK is attempting to break international law for the second time in a year.
The UK government is defending its decision to extend a grace period for food imports from Britain into Northern Ireland.
Yesterday it announced the period would be extended from April to October to help impacted businesses in the north.
European Affairs Minister Thomas Byrne says both sides need to work through the issue.
"When one side takes a unilateral action, and we've seen this a number of times since last summer, that creates huge difficulties for the peace process, and that's what we don't want to happen.
"It is essential that Britain and the European Union work together. The European Union has shown itself willing to engage in flexibilities to ease things in Northern Ireland.
"But the truth is that the protocol, the withdrawal agreement; they're international agreements that Britain signed up to, and it's incumbent on all of us to live up to our responsibilities."