Stormont’s First Minister has accused Ireland’s Foreign Minister of ignoring the views of unionists and assuming they will go away.

Arlene Foster urged Simon Coveney to reflect on remarks in which he said the EU could no longer trust the UK as a negotiating partner.

Mr Coveney was commenting on the UK Government’s decision to unilaterally extend a grace period limiting red tape associated with the movement of goods from Great Britain into Northern Ireland

Mrs Foster singled out Mr Coveney for criticism as she defended London’s move, insisting that Brussels was not listening to the concerns of people in Northern Ireland.

The DUP leader said the Fine Gael minister was ignoring Northern Ireland unionists.

“I listened with interest to Simon Coveney’s comments today,” she told a press conference in Dungannon.

“He talks about not having a partner you can do business with. I have to say he should reflect on that, because he’s not listening to the unionist people of Northern Ireland, the entirety of the unionist people of Northern Ireland.

“He’s ignoring them and thinking that they’ll just go away – well we’ll not go away.

“And we need to be listened to in relation to our very deep concerns about trade diversion.”

Mrs Foster also reiterated her criticism of Ireland’s deputy premier Leo Varadkar, referring to his use, when Taoiseach, of a newspaper article about a terror attack on a border post as he addressed fellow EU leaders on the reason why checkpoints on the island of Ireland needed to be avoided.

“What sort of message did that send to people? Was it that terrorism works?” she asked.

“Because I think that’s a very bad message to send. I said at the time it was reckless, I said it was very careless. But he did it. And I think that he needs to reflect on what he did.”

Earlier, Mr Coveney described the UK Government’s unilateral decision to extend an exemption period on Irish Sea border checks until October as “very frustrating”.

Speaking on RTE Radio 1, Mr Coveney accused the British of breaking the Northern Ireland Protocol and its own commitments.

“This is not the first time this has happened, that they are negotiating with a partner that they simply cannot trust,” he said.

“That is why the EU is now looking at legal options and legal actions which effectively means a much more formalised and rigid negotiation process as opposed to a process of partnership where you try to solve problems together, so this is really unwelcome.

“It’s the British Government essentially breaking the protocol, breaking their own commitments again, and the EU having to then consider how they respond to that.”

The first of the light-touch regulation schemes on goods from the rest of the UK moving to Northern Ireland had been due to expire at the end of March.

Supermarkets would have had to produce export health certificates for all shipments of animal products since Northern Ireland is part of the EU’s single market.

UK Cabinet member Lord David Frost said the UK’s intervention should allow time for constructive discussions with counterparts in Brussels.

Mr Coveney said the timing of the UK’s move could not be worse and that the British Government has “changed their approach”.

“They have decided to act unilaterally, which is clearly in breach of the protocol and the commitments that have been made only a few weeks ago,” he said.

Mr Coveney said he had a “blunt” conversation with Lord Frost and Northern Ireland Secretary Brandon Lewis on Wednesday after learning of the UK Government’s actions and “strongly advised them not to do it”.

“Before Lord Frost had even spoken in detail to Maros Sefcovic in his new role, this was announced in a written statement by the British Government in Westminster,” he said.

“To say that is disrespectful would be an understatement.”

Mr Coveney said he does not favour the EU taking legal action over the matter but the UK has left the EU with no option.

“I favour engagement, and engagement on the basis of trust between both sides, but if the UK simply cannot be trusted, because they take unilateral action in an unexpected way without negotiation, well then, the British Government leaves the EU with no option,” he said.

“This is not where we want to be but it is where the British Government is driving us towards.”