The UK's lead minister on the Northern Ireland Protocol has said it is "not sustainable" if it continues to operate as it currently does.
David Frost also warned that the British government was considering all its options in responding to how the Protocol was implemented.
The British minister in charge of post-Brexit relations was speaking after he made his first official visit to Northern Ireland.
He met a number of business and community representatives to listen to their experiences and to reaffirm the British government's commitment to address issues with the Northern Ireland Protocol.
Mr Frost and Britain's Northern Ireland Secretary of State, Brandon Lewis, visited Larne Port, a point of entry for goods moving from Great Britain to Northern Ireland, to see how checks and controls under the Protocol are currently being operated.
They also met Border Force and Department of Agriculture officials, and EU Commission staff present under the Protocol arrangements.
Throughout the visit, Mr Frost heard about the challenges in the operation of the Protocol and the consequent disruption for businesses and communities.
In particular, he heard concerns about the level and complexity of paperwork required even on goods remaining in Northern Ireland, notably in the agrifood sector.
He was also told about disruption to supply chains from Britain and consequent diversion of trade; and about the risks associated with the expiry of the grace periods and the introduction of further processes as a result.
The two ministers pledged to continue working closely with all sectors of opinion in Northern Ireland, including the Northern Ireland Executive, as talks with the EU Commission continue.
After the visit Mr Frost said: "It's clear from my visit that the Protocol is presenting significant challenges for many in Northern Ireland.
"Businesses have gone to extraordinary efforts to make the current requirements work, but it is hard to see that the way the Protocol is currently operating can be sustainable for long.
"We're committed to working through the issues with the EU urgently and in good faith," he added.
"I hope they will take a common sense, risk-based approach that enables us to agree a pragmatic way forward that substantially eases the burdens on Northern Ireland.
"Solutions must be found rapidly in order to protect the Belfast (Good Friday) Agreement in all its dimensions and to minimise disruption to the everyday lives of people in Northern Ireland - as the Protocol itself requires.
"As the Prime Minister [Boris Johnson] has made clear, we will continue to consider all our options in meeting our overriding responsibility for sustaining the peace and prosperity of everyone in Northern Ireland."
Reporting by Sean Whelan and Tony Connelly