With Brexit, goods can be brought into Northern Ireland and deemed “at risk” of moving down South. Once the goods arrive in Northern Ireland, a full declaration is submitted to HMRC and are then cleared into free circulation, meaning that the goods are able to move legally and freely anywhere on the island of Ireland- or even back into the EU.
The only other option to move freight via Northern Ireland and have the entry submitted to Irish Revenue instead of HMRC is by moving the cargo via a T1/T2 Transit document from Great Britain to ROI. This method however is more time consuming and has increased costs.
For more information on the above please visit the below link provided by Irish Revenue.