Cross-border shopping has slowed to a trickle and is now worth just 1.4% of retail spending nationally, Inter Trade Ireland has said.
The group released the results of surveys from shopping centres across Northern Ireland this week, showing the number of cars with southern registrations falling to the lowest level since September 2008.
The surveys, independently produced and not compiled directly by Inter Trade Ireland, cover shopping centres in Strabane, Newry, Enniskillen and Banbridge.
In early 2009 at peak hours almost 70 per cent of cars could have southern registrations, but this had now fallen to about 45 per cent.
Recent changes to VAT rates in the UK have also closed a gap between the two jurisdictions.
The organisation said the net loss to the Exchequer from shopping in the north was about €45m in VAT and €25m in excise, representing less than 5% of total VAT and excise receipts