LONDON: Britain wants to resolve issues with an agreement for post-Brexit trade with Northern Ireland as quickly as possible and will work "constructively" with the European Union, a spokesman for Prime Minister Boris Johnson said on Tuesday.

Britain has called on the EU for a reset in relations and a refinement of part of the Brexit divorce deal which covers trade with Northern Ireland, trying to seize the upper hand after the bloc was forced into U-turn in a row over COVID-19 vaccines.

After lawmakers in Northern Ireland complained about a shortage of goods since Britain completed its journey out of the EU's orbit this year, Michael Gove, in charge of implementing the Brexit deal, will meet European Commission Vice President Maros Sefcovic on Thursday to try to resolve the problems.

But relations are strained, not only by years of bruising Brexit talks but also after the EU threatened to draw a hard border for vaccines between Northern Ireland and Ireland - something it had long promised it wanted to avoid. The bloc quickly changed tack.

"We set out the issues we have currently ... We want to extend the existing measures but we are committed to working constructively and pragmatically with the EU to resolve the issues ... as quickly as possible," the spokesman told reporters.

Last week, Gove sent a letter to Sefcovic demanding some changes to the so-called Northern Ireland protocol of the Brexit deal, including an extension to grace periods for the transport of some chilled food from Britain to the province.

Earlier this week, Irish Foreign Minister Simon Coveney said Dublin was open to "modest" extensions of waivers on the movement of certain goods, but it is as yet unclear whether there would be agreement this week.

The spokesman declined to say whether Britain would agree to shorter extensions than those requested.