The European Union said on Monday that removing the oversight of the bloc's top court from the UK's Brexit deal in parts governing trade on the island of Ireland would effectively cut Northern Ireland off the European market.

"Our focus should be on those issues that matter the most to the people of Northern Ireland and not on requests such as removing the role of the European Court of Justice (ECJ)," a Commission spokesman told a news conference.

"Doing this would effectively mean cutting Northern Ireland off from the EU's single market and related opportunities."

On Saturday, British Brexit negotiator David Frost released extracts of a speech due this week, reiterating London's long-standing demand to remove any governing role of the ECJ from the EU-UK agreement regulating their new ties after Brexit.

The Commission said it would unveil this week concrete proposals to ease controls on trade coming from the UK province of Northern Ireland to EU member state Ireland, but that they would not deviate fundamentally from the Brexit deal in place.

(Reporting by Sabine Siebold and Gabriela Baczynska) ((Sabine.Siebold@thomsonreuters.com; +49-30-2201-33574;))