Britain and the EU will on Wednesday attempt to rescue a plan to calm post-Brexit tensions in Northern Ireland, after days of threats and accusations.

Lord David Frost, UK Brexit minister, and Maros Sefcovic, the European Commission vice-president, will meet formally to try to resolve issues around the post-Brexit trade border between Great Britain and Northern Ireland.

Ahead of the meeting British officials claimed Brussels was trying to “exploit” the imminent arrival of US president Joe Biden in the UK to put pressure on Frost to give ground in talks on the Northern Ireland protocol.

Frost said on Tuesday that “time is short” to make the new arrangements work. The protocol is the part of the 2019 Brexit withdrawal treaty the UK agreed with Brussels which seeks to avoid a hard border in Ireland by creating new checks on trade across the Irish Sea.

Biden arrives in Britain on Thursday ahead of the G7 summit in Cornwall and will hold talks with UK prime minister Boris Johnson. The White House has already confirmed that Biden will raise Northern Ireland at the meeting.

UK prime minister Boris Johnson and European Commission president Ursula von der Leyen discussed the disagreements over Northern Ireland in a call on Wednesday, during which they agreed to hold further talks in the margins of the G7. Von der Leyen warned after the call of her “deep concern” regarding the state of British efforts to implement agreements reached with the EU.

The Irish premier Micheál Martin on Tuesday called for both sides to “depoliticise” the protocol and treat the disagreements as technical trade problems to be overcome.

“It’s important that we do resolve these issues and that trust is built up between the European Union and the United Kingdom,” he said. “Otherwise we will have continuing issues and problems.”

For its part, Brussels warned EU diplomats at a closed-door meeting on Monday that Britain may soft-pedal on disagreements this week only to then act much more aggressively once the G7 and US meetings are over.

One diplomat told the FT that the fear expressed was that Britain might then go “full throttle” on Northern Ireland issues, including possible “unilateral measures” to dilute the protocol.

Frost earlier this week accused the EU of “legal purism” in its demands for how the protocol should be applied. The EU has said Britain is failing to implement basic parts of the new arrangements, such as building and properly staffing border control posts for goods, and sharing data with Brussels.

Johnson’s allies believe Brussels is trying to personally blame Frost — formerly Britain’s chief negotiator — for the bad atmosphere around the talks.

“They are playing the man not the ball but it won’t work,” said one senior British official. “David is actually quite moderate when you compare him to the PM. Boris takes a really hard line on all of this.”

But behind the scenes work has been intensifying to find what Frost called “practical solutions” to soften border controls on trade from GB to Northern Ireland. The minister was due to have a private dinner with Sefcovic in London on Tuesday.

On Wednesday the two will co-chair the first meeting of the new partnership council — set up to oversee the EU-UK trade deal — with a separate session to consider the operation of the Northern Ireland protocol.

The EU has emphasised that it is working intensively to find solutions to irritants thrown up by the protocol — it circulated papers to EU diplomats on Monday covering issues including VAT on second-hand cars, charges on steel imports, barriers to imports of British-made medicines, and veterinary checks.

Britain last week sent proposals to Brussels for a veterinary agreement to ease some post-Brexit checks on goods crossing into Northern Ireland from Great Britain — although the EU and UK remain far apart on how such an arrangement might work.

“First among these challenges is the damaging impact the protocol is having on the ground in Northern Ireland,” Frost said, claiming that trade across the Irish Sea for products such as chilled meat and medicines had been disrupted by the new border checks.

Referring to Sefcovic’s hints that the EU could retaliate with tariffs on British exports if the UK did not keep its side of the bargain on the protocol, Frost said “further threats of legal action and trade retaliation” were unhelpful.

Along with the Northern Ireland trade rules, the two sides will also discuss recent clashes over fishing rights around Jersey, while the UK will push for confirmation of its involvement in certain EU programmes, such as Horizon Europe science and research funding.