Minister for Foreign Affairs Simon Coveney has said Ireland will not be the collateral damage for irresponsible action taken by the British government over the Northern Ireland Protocol.
He told RTÉ's Six One News that the European Union is "going to be forced into responding in a way that it does not want to have to do".
His comments came as the British government published details of proposed legislation that gives ministers the power to override parts of the protocol.
European Commission Vice-President Maros Šefčovič warned it will "consider launching new infringement procedures that protect the EU Single Market from the risks that the violation of the Protocol creates for EU businesses and for the health and safety of EU citizens".
Mr Coveney said the Government will not allow a situation where Ireland becomes the "collateral damage of irresponsible British government politics".
We need your consent to load this rte-player contentWe use rte-player to manage extra content that can set cookies on your device and collect data about your activity. Please review their details and accept them to load the content.Manage Preferences
He added: "The last thing we want is rancour and disagreement with our closest neighbours in the UK, particularly [when] ... we should be working together in response to Russian aggression in Ukraine.
"Instead the British government has decided to trigger what is now a going to be a period of real tension between the EU and the UK and the UK and Ireland.
"A lot of the issues that were solved by the protocol through long and tedious and difficult negotiation and compromise, are now going to come back on the table, unfortunately.
"If the British government moves ahead with this legislation, and if it becomes law, [key] elements of the protocol that protect Ireland will be disapplied."
Mr Coveney warned that the EU is going to be "forced into responding in a way that it does not want to have to do" and that "we cannot and will not allow a situation where Ireland becomes the collateral damage of irresponsible British government politics, which is what we're seeing today."
The minister said the British negotiating team has not engaged seriously in negotiations since 11 February. "That's 123 days of no negotiation," he said.
"Instead of negotiating and compromising the British government has decided to go it alone."
Earlier, British Prime Minister Boris Johnson insisted that the plan to effectively override parts of the Brexit agreement with Brussels was "not a big deal".
Speaking on his way into Government Buildings this afternoon, Mr Coveney directly contradicted Mr Johnson. He retorted: "It is a big deal."
He characterised the British government's decision to unilaterally legislate on the protocol as an act of "bad faith" - something the Irish Government has been strongly advising against.
Mr Coveney spoke to Ms Truss by phone this morning, where she outlined her intention to publish the legislation today.
In a post on Twitter afterwards, he said the UK government is "proposing to set aside" international law, "reject a partnership approach, ignore majority in NI & deliberately ratchet up tension with an EU seeking compromise".
He added that the Government remains open to dialogue to find agreement, but that this approach "adds to instability" and "is no fix".
Spoke with @trussliz.
— Simon Coveney (@simoncoveney) June 13, 2022
UK Govt now proposing to set aside Int Law, reject a partnership approach, ignore majority in NI & deliberately ratchet up tension with an EU seeking compromise.
We remain open to dialogue to find agreement but his approach adds to instability & is no fix.
Taoiseach Micheál Martin said the only way to resolve the protocol impasse is through "substantive negotiation" and a breach of the protocol is "very serious".
Mr Martin said breaching an international deal ratified by the UK parliament and approved by its Prime Minister is "very serious".
He called on the British government to enter into discussions now, adding that Europe "has been flexible, and wants to find a resolution to these issues".
He said it was very regrettable for a country like the UK "to renege on an international treaty" saying it represents a "new low point between the natural expectations of democratic countries like ourselves honouring international agreements we enter into".
Unilateral breach of the Protocol is very serious - an international deal ratified by British Parliament and approved by the PM.
— Micheál Martin (@MichealMartinTD) June 13, 2022
It goes to the heart of the issue of trust.
The only way to resolve issues is by substantive negotiations between UK and EU. (1/2)
The Taoiseach also said that "essentially announcing the unilateral breaching of an international agreement is pretty serious stuff and can't be just sort of put to one side.
"It is a very serious issue because it goes to the heart of the issue of trust and the European Union needs to have a trusted partner to negotiate with."
He added: "Unilaterialism does not work. Unilaterialisim has never worked in the context of the Good Friday Agreement and I'm still very concerned that we are currently witnessing a denial of democracy where we have had an Assembly election and yet we don't have an Assembly convened.
"The people's voice needs to be reflected in the institutions being put in place, the Assembly in particular, and the Executive".
The UK move is designed to persuade the DUP to agree to go back into the power-sharing administration at Stormont.
DUP leader Jeffrey Donaldson has said he will only agree to do so if the protocol dispute is resolved to his satisfaction.
That seems unlikely at this stage. The proposed bill is expected to be "enabling legislation" to give British government ministers the power to override or set aside parts of the protocol at some future date, not with immediate effect.
It had been due to be published last week but is believed to have been delayed because of infighting within the Conservatives following an initial hardline draft proposed by Ms Truss.
Mr Donaldson and other senior DUP members have said repeatedly in recent weeks that they want "action, not words."
Additional reporting: Jennie O'Sullivan, PA
