Exporters are being urged to keep diversifying their business regardless of the outcome of the EU referendum.
With record overseas trade of more than 20 billion euro last year, state agency Enterprise Ireland reported homegrown firms have already felt the effect of uncertainty around the Brexit vote.
Half of the record exports from Irish companies are now in the food sector.
But Enterprise Ireland said diversification of trade into Northern Europe, the US and high-growth markets such as China, India, the Gulf and Brazil was paying off.
It said exports to the UK shrank from 45% of overseas sales in 2005 to 37% last year.
Julie Sinnamon, Enterprise Ireland chief executive, said Irish exporters were a big success story with record levels of business being won internationally.
“Significantly, growth was recorded across all sectors and we are seeing that diversification into high growth markets is a focus for our clients,” she said.
“The UK remains our largest export market, but we are seeing a trend whereby the exports to the UK as a proportion of our total client exports has declined.”
But Ms Sinnamon added: “There are a number of risks to the continued growth in exports and the uncertainty associated with the UK referendum has already had an impact on clients exporting to the UK.
“We are hopeful that the UK will remain within Europe, but we will continue to work on our strategy over recent years of supporting our clients to diversify into new markets.”
A review of 2015 exports showed business in the US and Canada soared by 27% to almost 3 billion euro while exports to the UK grew 12% to 7.5 billion euro and those to Northern Europe grew by 8% to 4.2 billion euro.
Enterprise Ireland is targeting 22 billion euro of exports this year.
Jobs Minister Mary Mitchell O’Connor said: “Irish companies continue to deliver for the Irish economy and the figures announced today show the strength and capabilities of Irish companies competing at a global level.”