Northern Ireland is the number one destination for exports from the Republic of Ireland, according to new research.
InterTradeIreland's 'cross-border trade and supply chain linkages' report found that 51% of Republic exporters ship more than half of their goods to Northern Ireland.
The report also found that more than a quarter of Republic firms ship almost all of their exports (95%) to here.
Northern Ireland accounts for between 10% and 12% of the total exports from the Republic to the UK as a whole, and accounted for between 7% to 8% of imports, according to the figures.
The report found a significant share of cross-border trade is accounted for by firms which trade simultaneously in both directions.
These two-way traders make up around 18% of firms, however they accounted for over 60% of exports, and over 70% of imports.
The report highlights a high level of product turnover among trading firms which regularly introduce new products to the market, with many goods traded for one year only.
This pattern is consistent across companies of all sizes, as well as between food and non-food firms - showing a high degree of innovation among cross-border traders.
Companies that trade across the border were also revealed to be more likely to introduce new goods and services, with 35% introducing products for just one year
Aidan Gough, director at InterTradeIreland, said: "This report shows the disproportionate importance of cross-border trade for businesses across the island.
"The high degree of connectivity in supply chains, which the report underlines, shows the importance of firms planning for a number of post-Brexit scenarios."
He added: "Now is not the time for complacency or apathy in relation to Brexit."