Top European Union politicians must ensure there is no Mercosur deal on beef while Brexit remains unresolved, the Ulster Farmers' Union has said.
The comment came as European Commission officials hold talks in Uruguay with prominent South American politicians representing Mercosur.
The Latin American trade bloc consists of Brazil, Argentina, Paraguay and Uruguay.
UK farmers have frequently blasted the trade talks between the EU and Mercosur, who say that the South American countries do not come close to matching the food safety, animal welfare or environmental standards which farmers comply with in the UK and across Europe.
Ulster Farmers’ Union (UFU) beef and lamb chairman, Sam Chesney said farmers work hard to maintain world-leading standards.
“Local farmers have invested to make sure they deliver what consumers want and this cannot be ignored or set to one side by Brussels,” Mr Chesney said.
He added that these standards do not apply in South America, warning that the big players there, led by Brazil, would use the weakness of their national currencies to mount an export drive into Europe.
“No one is opposed to international trade deals. Farmers realise the global opportunities potentially available to our industry,” said Mr Chesney.
“But we cannot support trade negotiations taking place on an uneven playing field that sacrifice European agriculture for the supposed wider benefits for the eurozone of free trade with South America.”