A DUP MP has asked British government ministers if they should "slap down" the Tánaiste amid claims that comments by the Irish government were undermining confidence among unionists.
Ian Paisley pressed Northern Ireland minister Chloe Smith over an editorial in the Belfast News Letter that said comments by Simon Coveney were destabilising the economy in Northern Ireland.
Northern Ireland questions in the Commons also saw the Government's approach to Brexit branded "a shambles" by Shadow Secretary of State Owen Smith, given its position over the Common Agricultural Policy.
North Antrim MP Mr Paisley said: "Does the minister of state agree with the editorial in the News Letter this week, Britain's oldest running newspaper, which stated categorically that Mr Coveney, the deputy prime minister of the Republic of Ireland, needs to be slapped down by Her Majesty's Government for the comments that it is making, that is destabilising the economy of Northern Ireland?"
Ms Smith sidestepped the question, saying: "I think the simplest thing to say here is we stand behind, fully behind, the Belfast Agreement.
"We do have a strong relationship with the Irish government which we wish to see continue."
She added that she wanted to see devolution restored in Northern Ireland.
Paul Girvan (South Antrim), another DUP MP, said: "In light of recent comments by the Irish prime minister and the secretary of state, the Irish prime minister and deputy prime minister, Mr Coveney and Mr Varadkar, they have indicated that they will draw a border down the middle of the Irish Sea.
"Can I ask that those sorts of comments do not give much confidence back to the people of Northern Ireland, and the unionist community that I represent, who want to be an integral part of the United Kingdom."
Ms Smith reiterated that the British government wanted to see no new borders inside the UK and that the UK and Irish governments were close partners.
Elsewhere in the session, Secretary of State James Brokenshire said Britain would be leaving the Common Agricultural Policy in 2019, while maintaining payments through to 2020.
Labour's Mr Smith said: "That cannot be correct.
"It cannot be right that we will both be under exactly the same EU rules and regulations, which is what the prime minister said in Florence, and that we will be leaving the Common Agricultural Policy.
"If it is true that we are leaving the Common Agricultural Policy, 30,000 Ulster families and farmers need to know how they're going to pay their mortgages and meet their other commitments in just 15 months' time.
"This is a complete shambles. The prime minister is going to be here in a minute. Can he tell her to sort this out?"
Mr Brokenshire replied: "The only shambles is the approach of the opposition to Brexit.
"I know at this of the year that many people will mark the 12 days of Christmas, but we've had at least 12 different approaches on Brexit from Labour.
"I say to him that yes, we will be leaving the Common Agricultural Policy as the prime minister said on Monday, but she also underlined clearly our commitment in relation to those direct payments."