The EU Commission will respond to newly published UK protocol legislation in an “incremental way”, Taoiseach Micheál Martin has said.
The EU is now expected to launch legal action against the UK over its breach of international law and a trade war between London and Brussels may take place as a result.
Mr Martin said the “main losers” of the protocol being changed are the people of Northern Ireland and the lack of an Assembly is a “denial of democracy”.
“The main losers of this are the people of Northern Ireland, of that I have no doubt,” he told reporters at Dublin Castle.
“The European Commission will respond in an incremental way to what has transpired.”
He said it is “obvious” that there is a “political agenda” in Westminster and this is the reason for the British Government’s refusal to enter negotiations with the EU.
“There is political agenda within London, it seems fairly obvious at this stage,” he said.
“The only way to resolve this is substantive negotiation between the British government and the European Union.
“Clearly, that forum is always there to resolve through negotiation. But there has been an absence of will from the British government to resolve this through negotiation and it’s time now for those substantive negotiations to commence.”
Mr Martin said it is “very serious” that a Stormont Assembly has still not convened in Belfast.
Despite Sinn Féin being voted the largest party in the recent election, the DUP has refused to enter a power-sharing executive until the British government resolves issues with the Northern Irish Protocol.
“Parallel with this, we have the continued denial of democracy in Northern Ireland, the people of Northern Ireland have spoken through the ballot box. They want their assembly convened and they want the Executive convened,” Mr Martin said.
“That’s a very serious situation, where democracy is being denied.”
DUP leader Sir Jeffrey Donaldson said the Irish Government needs to "get real" about the problems being caused by the Northern Ireland Protocol.
Mr Donaldson said Foreign Affairs Minister Simon Coveney “fails” to recognise the extent of the problems that the protocol is causing for Northern Ireland.
"It is not just about trade, it is not just about the difficulties it is creating for business, it is not just about the impact this is having on the cost of living for every consumer in Northern Ireland, it is also about our political institutions,” he told BBC's Good Morning Ulster.
"It is about stability. Not a single unionist MLA elected to the Assembly last month supports the protocol and without that cross-community consensus the political institutions cannot operate.
"I think the Irish Government need to get real, they need to understand the extent of the problem here and stop deluding themselves that it is some kind of minor issue.
"As for negotiations, Simon Coveney talks about sitting around the table; the problem is we've had two years of negotiation and no progress."
Minister Coveney told the same programme that the UK Government's legislation would “dismantle” the Northern Ireland Protocol.
Mr Coveney said the British Government is now looking to “undermine all of that work for whatever political reason”.
"What the British Government is proposing to do is dismantle the protocol, which is international law, which was carefully put together over a number of years through painstaking negotiation involving this British Prime Minister to solve or to manage the disruption of Brexit on the island of Ireland as best we could,” he said.
"But it is being warned from Ireland, from all EU capitals, from the European Commission, from the White House, all of Britain's friends are effectively saying please don't do this.
"A majority of people in Northern Ireland, where 52 of the 90 MLAs wrote to the Prime Minister yesterday to say please don't do this.
"Business leaders in Northern Ireland and business leaders in the UK have said please don't do this.
"It is going to destabilise what is already a difficult situation and instead focus on negotiations with the EU who want to compromise and want to respond to unionist concerns."
Meanwhile, Sinn Féin's leader in Northern Ireland, Michelle O’Neill, said everyone "bar the DUP and Boris Johnson" knows that the protocol is working.
Ms O’Neill described the actions of Mr Johnson and Foreign Secretary Liz Truss as "disgraceful and utterly reckless".
She added that the DUP and Mr Johnson are undermining the peace process at every turn.
"It is a straight up, slam dunk breach of an international agreement, it undermines the Good Friday Agreement, and their actions will have huge economic consequences,” she told RTÉ’s Morning Ireland.
Ms O’Neill said the actions of Mr Johnson serve to create “more instability and uncertainty” for businesses trying to plan for the future.
"Any of the actions that I note that Boris Johnson takes over the course of weeks and months and even years now, has been at every turn to undermine the Good Friday Agreement," she said.
"I personally feel like it's under full frontal attack by this Tory government who care less for the needs of the people who live on this island, who care less for the fact that the Good Friday Agreement has delivered such transformational change over the last 24 years."
Ms O’Neill claimed that the DUP is in a “stand-off” with the public over the party's refusal to form an Executive.
“They’re punishing the public by staying out of an executive that could actually help people through this cost-of-living crisis, that is not a tenable position for them to take,” she said.
“The rest of us are there every day, all the other parties who want to work together, who want to form an Executive believe that we can do all of that.
"We should be encouraging ongoing continued conversation between the EU and the British Government to find agreed solutions.
"Not this reckless approach of Boris Johnson, who has not even engaged in any meaningful negotiation to find an agreed solution since February of this year."
Additional reporting by PA