Brexit will have major cross-border trade implications for farming and food, according to Alliance party leader David Ford.
"Agriculture and food will be the sectors most exposed to these challenges if a hard border becomes a reality over the coming years," he said.
Mr Ford made the comments while visiting this year's Antrim Show.
He sits on the new agriculture, environment and rural affairs committee at Stormont.
"The reality is that the Irish border immediately becomes an international frontier between the EU and the United Kingdom post-Brexit.
"And this will have major implications for the way that we in Northern Ireland go about our business.
"Farming and food already operate on an all-island basis, to a large extent."
Mr Ford welcomed the merger of both agriculture and environment within the new ministerial and departmental arrangements at Stormont.
"Both policy areas fully complement each other," he said.
"Irrespective of the UK coming out of the EU, the fact remains that local farmers will have to attain the highest environmental standards when it comes to producing food."
Meanwhile, in the show rings, the McLean family, from Bushmills, were having another excellent day out.
They won their fifth inter-breed dairy championship of the summer with the Ayrshire 4th calver, Marleycote Sea Lilly.
The judge, Robert Hunter, from Lanarkshire, described the cow as an excellent example of the Ayrshire breed.
"The fact that she has calved successfully on four occasions, and still looks so well, is testimony to her tremendous dairy strength," he said.
"Longevity is so important from a dairy breeding perspective.
"We milk Holstein and Jersey cows at home. So it takes a truly outstanding animal of another breed to catch my eye."
Dromara flock owner Jim Aiken will also have fond memories of Antrim Show 2016.
He won his second inter-breed sheep championship in successive weeks with the same animal, a truly eye-catching Border Leicester shearling ewe.
Judge Kevin Buckle, from Cumbria, described the animal as one having outstanding breed characteristics.
"In addition to her tremendous conformation, she has effortless grace and poise. She stood out from all the other sheep that qualified for the inter bred class," he said.
The beef inter-breed championship was won by the Connolly family from Ballynahinch in Co Down, with their outstanding Charolais cow, Wesley Glamorous. She was accompanied in the show ring by her fifth calf, born just a few weeks ago.