Cabinet Minister Michael Gove has said the government will ensure NI businesses will have “unfettered access” to the UK market after Brexit.
He met the leaders of all the devolved regions in Cardiff on Tuesday.
First Minister Arlene Foster and Deputy First Minister Michelle O’Neill raised concerns about the possibility of checks on goods crossing the Irish Sea.
Mrs O’Neill said they were there “to show that we don’t want any barriers to trade for our local economy”.
It came a day after the EU’s chief negotiator, Michel Barnier, said new checks on goods entering Northern Ireland from Great Britain are an “indispensable” consequence of the Brexit deal.
Speaking after the meeting, Mr Gove told BBC News NI: “We will make sure that the unfettered access that we want to have for goods circulating within the UK is absolutely protected.
“We will do everything we can in order to provide Mr Barnier with all the information he needs to recognise how that’s going to work.”
The prime minister had suggested that GB-NI trade would remain unfettered but Mr Barnier said that the UK’s choices make frictionless trade impossible.
Northern Ireland Secretary Julian Smith reiterated Boris Johnson’s sentiments.
“We will be in the UK customs union and we will be legislating to ensure unfettered access and we will deliver that,” he said.