The Mercosur trade deal, which was controversially opposed by Ireland has "positive aspects" which will overcome its other features, the former Italian Prime Minister Enrico Letta said while on a visit to Dublin.
Last month Government voted against the trade deal between the EU and four South American countries following strong objections from the farming lobby.
The European Parliament voted for the European Court of Justice to assess whether the deal meets EU treaties which could hold the deal up.
Mr Letta said Mercosur was part of a broader policy of opening trade links which should be part of the EU's response to US President Donald Trump.
"The main reaction to Trump has to be: one Europe one market, second opening trade routes...third showing that we can support Ukraine standing alone," he said.
Mr Letta was speaking at the launch of COMPETE the Jean Monnet Centre of Excellence in Dublin City University coordinated by the Dublin European Law Institute.
The former Italian Prime Minister, who authored a report on revamping the Single Market, met the Minister of State for European Affairs Thomas Byrne today and met Taoiseach Micheál Martin last week.
He said the Irish presidency of the European Union will play a "critical role" in the acceleration of the Savings and Investment Union, which is the EU’s project aimed at creating more integrated financial systems.
Speaking to the media in DCU, Mr Letta said Ireland’s presidency would also be important for greater integration of energy and connectivity.
Ireland is supportive of the Savings and Investment Union although the Taoiseach last week there were concerns about a single supervisor authority for the project.
Mr Letta said some countries including Ireland had "some doubts" and "scepticism" about the supervisory system.
But he said the Savings and Investment Union should use a similar model as central banks where national authorities cooperate with a central authority.
Mr Letta said taking steps accelerate competitiveness would reach a "crucial moment" during Ireland’s presidency.
He added: "The most effective reaction to Trump is to create one market."
