Eleven of the 15 European Union goods most exposed to Britain are Irish exports, analysis by the Finance Department showed today, highlighting the extreme vulnerability to Brexit for some Irish firms.
With close trading links to Britain and a shared land border, Ireland is widely considered the EU member most at risk after Brexit.
Irish businesses fear Brexit will lead to a costly rise in tariffs, paperwork and transit times.
The UK accounts for around 17% of Irish exports, but that figure leaps to 44% when foreign-owned firms are excluded.
Employment-heavy industries in rural areas are also among the most reliant on trade across the Irish Sea.
Products of Ireland's agri-food sector are among the EU's most exposed to Brexit, the research showed, led by cereals, fruit and vegetables, almost 90% of which are exported to the UK.
High volume Irish industries such as meat, dairy products, the live animal trade and wood manufacturing are also among the most exposed.
Cyprus and Malta are the only other two EU member states whose goods feature in the top 15.
The research also found that although Irish trade has become far less reliant on the UK since the early 1970's, when the UK accounted for over 50% of total exports, some big sectors have increased their share of exports.
The proportion of food and live animal exports to the UK increased to 46% in 2015 from 38% in 2000, while exports in manufactured goods rose to 55% of the sectors' total exports from 43% over the same time.
Irish agri-food would face some of the highest tariffs if the EU-registered World Trade Organisation tariff schedule was applied to EU-UK trade should Britain leave under a so-called "Hard Brexit" in 2019, the report noted.
Agri-food and traditional manufacturing face an additional vulnerability due to the UK's reliance on the two sectors, the report added, as outside the EU, Britain would have an incentive to seek trade agreements with third countries on better terms in areas in which it is not self-sufficient.
The Government has called on Britain to stay in the EU's customs union to maintain the currently invisible border with Northern Ireland, an outcome that would also limit disruption for exporters.
But with Britain insisting it will leave the EU's trade bloc, Dublin has also been introducing measures to encourage firms to diversify into other markets.