The EU expects the UK to put measures in place to ensure goods crossing the Irish Sea are being monitored and checked for customs and regulatory compliance post-Brexit, a briefing paper suggests.
And the EU will monitor the extent to which EU law continues to operate in Northern Ireland after the post-Brexit transition period, RTE has reported.
An EU briefing document also says that IT systems and databases will track goods moving to the North from Great Britain.
The working paper was circulated by the European Commission in advance of free trade negotiations with Britain, due to start in March, RTÉ reports.
The document describes the Irish Protocol, agreed between the EU and UK, as "a fully legally operative solution for Northern Ireland…to remain in the UK's customs territory" but one in which Northern Ireland would "apply the [European] Union’s Customs Code (UCC), as well as checks and controls, on all goods coming from third countries as well as from Great Britain…"
The North will "remain aligned to the relevant EU rules (customs, sanitary and phytosanitary rules, regulatory compliance, state aid, VAT and excise rules)."
The Protocol "avoids a hard border on the island of Ireland, protects the all-island economy and the Good Friday Agreement in all its dimensions, [and] safeguards the integrity of the Single Market," the paper says.
Last October British Prime Minister Boris Johnson said there would be a regulatory and customs border on the Irish Sea.
The withdrawal agreement says EU and UK officials in a joint committee will implement the treaty.
The working paper describes how the joint committee will operate, and also sets out the creation of six specialised committees, one to deal with Ireland.
The Irish Protocol foresees tariffs and customs on goods moving between Great Britain and the North, as well as regulatory checks and controls.
However, the joint committee will suggest goods to be exempt from tariffs if there is no risk to them entering the EU single market overland.
This will be the second track envisaged in the blueprint.
If the UK and EU reach a zero-tariff, zero-quota free trade agreement, tariffs will be removed though checks and controls will still apply.