The controversial EU-US trade deal known as the Transatlantic Trade and Investment Partnership (TTIP) could boost Irish gross domestic product by around 2%, Ibec boss Danny McCoy told a conference yesterday.
The boost would be twice as big as the European Union average and would help large SMEs the most, added Mr McCoy, who leads the Republic's employer and business organisation.
TTIP is on course to turn the EU and US blocs into the largest free-trade area in the world.
The Republic's Enterprise Minister Richard Bruton told the same seminar in Dublin yesterday that TTIP offers "massive opportunities" for the Irish economy.
Research by Copenhagen Economics has shown that a comprehensive trade agreement with the US would create up to 10,000 extra jobs, he added.
MEP Sean Kelly said a deal would be especially beneficial to smaller companies.
"I would like to see the TTIP negotiations focus on a strong harmonisation of business regulations, as it could go a long way towards SME growth," he added.