There would be "serious consequences" for EU-UK relations if London tries to suspend the parts of the post-Brexit deal covering Northern Ireland, a senior European Union official has warned.

"There'll be no doubt that triggering Article 16 to seek the renegotiation of the protocol would have serious consequences – serious for Northern Ireland... and serious also for the EU-UK relations in general," EU Vice President Maros Sefcovic said after meeting the UK's Brexit Minister David Frost in Brussels.

The UK government has been unhappy with the impact of new border checks on goods passing from the rest of the UK to Northern Ireland, the only part of the UK with a land border with the European Union.

The arrangement was agreed as part of the Brexit deal as a way to avoid the return of physical border posts and checks on the island of Ireland while also meeting the EU's requirement for tighter controls to protect its single market of 450 million people.

Britain says the checks are disproportionate and heightening tensions in Northern Ireland and putting at risk the 1998 peace deal between Irish Catholic nationalist militants and pro-British Protestant "loyalist" paramilitaries.

Ahead of the meeting, Frost said the UK would not on Friday trigger the emergency provision (Article 16), which allows either side to take unilateral action if they believes the agreement on post-Brexit trade is having a negative impact on their interests. But he added: "Article 16 is very much on the table."

Frost said the best way of avoiding that move was "if we can reach an agreement, an essential agreement ... that provides a sustainable solution."

He said there was a "significant" gap between the EU and the UK on the matter and that time was running out for his negotiations with Sefcovic, a deputy head of the bloc's executive European Commission.

A UK government spokesperson later said the two men would meet for further talks next week in London, adding that "in the UK view, these gaps could still be bridged through further intensive discussions."