London - The UK and the European Union have agreed a scheme to ease the flow of goods between mainland Britain and Northern Ireland after Brexit, London says.

Trading arrangements for Northern Ireland have been a major sticking point in the Brexit process given that it will have Britain's only land border with the EU from January 1.

The prospect of imposing tariffs on all goods travelling to Northern Ireland from mainland Britain arose because of the risk of them crossing into the EU's single market, via member state Ireland.

But London said Wednesday that was unacceptable, as it would cut Northern Ireland off from the rest of the UK.

Senior UK minister Michael Gove confirmed that a deal agreed with Brussels this week ensured Northern Ireland business "will be free of all tariffs".

"British sausages will continue to make their way to Belfast and Ballymena in the New Year," Gove told lawmakers.

Map of Northern Ireland and the border with the Irish Republic

He also said a "trusted trader" scheme would "guarantee goods being sold in Northern Ireland and businesses operating in Northern Ireland will face no tariffs".

Irish state broadcaster RTE said the exemptions of tariffs would cover up to 98 percent of goods moving from England, Scotland and Wales to Northern Ireland from January 1.

"The other two percent would potentially avail of rebates from any tariffs," it said, adding the charges would mostly apply only in case Britain and the EU fail to reach a free trade deal in separate talks.

A deal remains elusive, despite months of negotiations ahead of a December 31 deadline for one to be in place in time for the New Year.

The separate agreement on Northern Ireland trade allows for some EU officials to be present at ports in the province as observers, but UK officials said they will not be allowed to carry out checks themselves.

Neither will they be allowed to wear uniforms, and Gove said there was no prospect of the EU setting up a "mini embassy" in Northern Ireland, a prospect that has been denounced by Brexiteer lawmakers in the ruling Conservative party.

"Limited and proportionate border facilities" between Northern Ireland and Ireland would be in place to conduct some checks on the transport of food and animals, Gove added.

Keeping the border open, free of infrastructure and customs checks, was a key plank of the 1998 Good Friday Agreement that largely ended 30 years of violence over British rule in Northern Ireland.