Irish Foreign Minister Simon Coveney has warned the UK it will be making "a really big mistake" if it breaches the Northern Ireland Protocol.
London is poised to reintroduce elements of its controversial Internal Market Bill, which could override the protocol in a move that would breach international law.
The UK is also set to table its Finance Bill, elements of which could also breach parts of the Northern Ireland Protocol - designed to prevent a hard border - agreed last year.
It comes amid an intense period of negotiations between the EU and the UK to reach a post-Brexit trade deal.
Mr Coveney said yesterday that such a move by the UK would be taken as a "clear signal" by the EU that Britain does not want a deal.
"I think if they do that, it will be a clear signal to the EU that this process is not going to conclude well," he added.
"It will be a signal that they effectively don't want a deal. I really hope that doesn't happen.
"We have given signals, in as respectful and blunt a way as we can, that that would be a really big mistake at this stage in negotiations.
"I think Michel Barnier's briefing of the meeting this morning would reflect that too."
Earlier, EU chief negotiator Mr Barnier reportedly briefed European ambassadors that a breach of the Northern Ireland Protocol would trigger a "crisis" and cause a breakdown in trust.
Mr Coveney told an Oireachtas committee that an agreement on the implementation of the protocol was close. He was heavily critical of the UK Government's actions around the Internal Market Bill, which he said had damaged their reputation internationally. "We could have a second piece of legislation that doubles down on the issue through the Finance Bill next week, in the context of another element of the protocol," he explained.
"I think the EU will draw only one conclusion if that course of action happens, which will be hugely regrettable."
Separately, an SDLP MP suggested the UK Government appeared to have an "unlimited disregard" for the Good Friday Agreement.
Raising the issue in the Commons yesterday, South Belfast MP Claire Hanna also pressed Secretary of State Brandon Lewis to rule out any undermining of the Northern Ireland Protocol.
Ms Hanna said: "We know that the Internal Market Bill intends to breach international law and yesterday it was indicated that a further breach of international law was likely to come in the Taxation Bill.
"Far from being limited and specific, it seems the disregard for the Good Friday Agreement is unlimited while people desperately want certainty and a deal.
"Can (Mr Lewis) give us any assurances that next week's Bill won't further undermine the protocol, the chances of a deal, and the certainty and stability that people so desperately want?"
Mr Lewis said clauses in the Internal Market Bill were "about actually protecting and delivering on the Good Friday Agreement to ensure there are no borders, and it is important that we have no border, not just north-south but east-west as well, to deliver that."