Britain and the EU are expected to meet this week for talks on the future of trade in Northern Ireland as the arrest of two men added to growing political unease in the region.
Cabinet Office Minister Michael Gove is set to welcome the EU Commission's Maroš Šefčovič in London where they will discuss issues surrounding the implementation of the Brexit withdrawal agreement.
Last week, the EU was roundly criticised for a bungled attempt to stop the flow of the AstraZeneca vaccine into the British province in a row over its distribution.
Slogans condemning an ‘Irish Sea border’ appeared in various areas of the port town of Larne on Saturday, prompting the Police Service of Northern Ireland (PSNI) to carry out searches of the area and led to two arrests.
Two men, aged 21 and 25, were charged with criminal damage near to the port where the politically contentious Brexit import checks are being carried out. The pair will appear before court later on Monday.
Last week, checks on goods were suspended at Larne after workers were threatened by hard-core unionist groups opposed to the Brexit deal, which has imposed a de facto border for goods and services between Northern Ireland and the UK mainland. Mr Gove told parliament that any intimidation of workers at Belfast and Larne ports was "completely unacceptable".
Meanwhile, new coronavirus restrictions came into force on Monday preventing people in Northern Ireland crossing the border into the Republic. Irish police have warned they will impose a €100 (£88) fine on anyone caught flouting the rules without a “reasonable excuse”.
Brexit is having a profound impact on businesses on Northern Ireland which have had to adapt to new trading arrangements, including new systems for companies and officials. Some businesses have struggled with new customs declarations and health certificates as the coronavirus pandemic also hits firms.
International members of the Road Haulage Association (RHA) reported a 68 per cent fall in exports in January, the group wrote on Twitter, after Brexit deal took effect.
"I find it deeply frustrating and annoying that ministers have chosen not to listen to the industry and experts," RHA Chief Executive Richard Burnett told The Observer newspaper.
Meanwhile, Ireland is open to "modest" extensions of waivers on the movement of certain goods from Britain into Northern Ireland after the British government asked the EU to tweak post-Brexit rules, Irish Foreign Minister Simon Coveney said.
"I would be open to advocating for modest extensions of grace periods," Mr Coveney told Ireland's RTE Radio, but he said there was no question of scrapping the Northern Ireland Protocol of Britain's EU divorce deal.