The Prime Minister has said he is willing to override part of the Northern Ireland Protocol to ensure that there is no post-Brexit trade barrier down the Irish Sea.
DUP North Antrim MP Ian Paisley said his constituents had been made to feel like foreigners in their own country.
Urgent action from the European Union is needed to resolve the problems, Boris Johnson acknowledged.
The agreement on post-Brexit trade to keep the Irish land border open has caused disruption to goods travelling from the rest of the UK but progress has been made in recent weeks.
Mr Johnson said: “We will do everything we need to do, whether legislatively or indeed by triggering Article 16 of the protocol, to ensure that there is no barrier down the Irish Sea.”
Article 16 is part of the post-Brexit deal which keeps Northern Ireland following the EU’s customs rules.
It is designed to allow the EU or Britain to intervene unilaterally if the protocol is causing a major problem within its borders.
The Democratic Unionists have been pressing for it to be invoked in response to strains on east to west trade which emptied some supermarket shelves temporarily following the end of the post-Brexit transition period and interfered with the transit of parcels.
Mr Paisley told the House of Commons: “Prime Minister, you say that your commitment to Northern Ireland is unshakeable.
“But I speak for all of my constituents today when I tell you that the protocol has betrayed us and has made us feel like foreigners in our country.
“Tea and sympathy will not cut the mustard.”
The Prime Minister spoke to Stormont First Minister Arlene Foster on Wednesday morning.
A Downing Street spokesman said: “The Prime Minister said that we needed urgent action from the EU to resolve outstanding problems with protocol implementation, so as to preserve the gains of the Belfast Good Friday Agreement and to ensure that Northern Ireland benefits in full from the UK’s exit from the EU.”
They discussed their shared concern that processes established in the protocol were ignored when Brussels threatened on Friday to override part of the deal and stop coronavirus vaccine supplies crossing the border from the Republic.
The Prime Minister told Mr Paisley: I utterly share the frustration of the honourable gentleman about the way the EU, in particular, the EU Commission, temporarily seemed to call to use the protocol in such a way as to impose a border contrary to the spirit of the Good Friday Agreement, and contrary to the letter of the Good Friday Agreement.”
The Prime Minister urged that coordinated work with Cabinet Office minister Michael Gove continues to ensure the protocol worked in the interests of the people of Northern Ireland.
A DUP spokesman for Mrs Foster said Mr Johnson had indicated he wanted to resolve the outstanding issues by the end of next month.
“The Prime Minister indicated that he was deeply shocked ‘by the cavalier approach adopted by the EU’ last Friday and without consultation,” the party statement said.
“He recognised that such actions by the EU undermines the authority of the protocol.”
The DUP added that it was plain the protocol was being used in an “absurd” way.
Sinn Fein Deputy First Minister Michelle O’Neill said it was time for steady, calm and measured leadership from all political parties amidst unionist discontent.
“Our businesses and citizens deserve certainty and I am committed to working to provide that.”
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules here