Britain said on Wednesday it saw no need for new customs infrastructure in Northern Ireland but checks would be made on some goods heading to the province from the mainland in its proposals for how the border will work from next year.
Britain left the EU in January and has until the end of this year to negotiate an agreement on future ties or start 2021 without a trade agreement, which some businesses say could cause costly delays and confusion at borders.
Northern Ireland, which is part of the United Kingdom but shares a land border with EU member Ireland, hampered any agreement between Britain and the bloc until late last year when Prime Minister Boris Johnson agreed to a so-called protocol.
The EU says the protocol requires strict customs checks and tariffs on some goods coming from mainland Britain into the province in case they are headed onwards into Ireland and the bloc's single market.
But before December's election, Johnson told businesses in Northern Ireland there would be no barriers in the Irish Sea and they could put any customs declarations "in the bin".
In its proposals for how the protocol would operate, Britain said Northern Ireland would remain part of its customs territory and businesses would have unfettered access to the rest of the United Kingdom.
However, the government added traders would face "some limited additional process on goods arriving in Northern Ireland" from mainland Britain.
There will be tariffs levied on goods entering the province from the rest of the United Kingdom but only if they were destined for Ireland or beyond or "at clear and substantial risk of doing so", the protocol plans said.
It said there would be no new customs infrastructure while accepting some existing checkpoints for agrifoods would need to be expanded.
Cabinet Office minister Michael Gove said such checks would be "as light touch as possible".
The aim of the protocol was to ensure no return to a hard border between Northern Ireland and the Irish Republic, seen as key to avoiding an undermining of a 1998 peace accord which largely ended three decades of sectarian and political conflict.
(Reporting by Elizabeth Piper and Michael Holden; editing by Stephen Addison and Angus MacSwan)
