The Taoiseach Leo Varadkar has said Ireland's agri-food sector is "uniquely exposed" due to Brexit.
He was speaking at the Irish Farmers Association AGM in Dublin on Tuesday.
He told delegates: "Everyone in this room is aware of the long-term, structural and disruptive changes that could happen as a result of Brexit.
"Some industries are significantly more exposed, like beef.
"Even in the absence of tariffs, barriers such as sanitary and customs controls, transport logistics and shelf life, are much more significant barriers for food than for other exports."
Some 35% of Ireland's total agri-food exports, worth over €4.4bn, are to the UK.
He added: "That is why we negotiated so long and so hard in the weeks before Christmas. At stake is the future of Ireland, our peace and prosperity.
"In a hard Brexit scenario food exports could, in theory, face very high tariffs. That would be catastrophic and must be avoided."
"The ongoing uncertainty is bad for business planning, particularly for people thinking of investing.
"So, over the last two budgets, the Government has taken action to assist business, and farming in particular, to navigate the challenges of Brexit."
He said: "Brexit underlines the importance of pursuing and developing new markets for Irish agri-food exports. But it's actually something we should be doing anyway.
"In order to do this, we must gain a deep understanding of what consumers, often in distant markets, really want, and communicating those messages back to Irish farmers and food companies.
"This is why we are doubling the Team Ireland footprint overseas by 2025."
He said the Government has invested almost €15m into Bord Bia, for the development of 'Thinking House' - a consumer research and market insight centre.
Mr Varadkar pointed to "an intensified series of trade missions" to establish relationships with countries both within and outside Europe.
"We have developed new markets. The United States is now our second biggest market, and China our third.
"So by pursuing an ambitious global strategy we have grounds for real optimism at home."
