The Irish National Ploughing Championships is "a great place to do business", Stormont Agriculture Minister Michelle O'Neill has said.
Billed as Europe's largest outdoor exhibition and agricultural trade show, organisers expect more than 200,000 visitors over the course of three days.
More than 100 Northern Ireland firms are among about 1,400 exhibitors.
Mrs O'Neill said the County Laois event was an excellent opportunity to "showcase what they have to offer".
"Fundamentally this event focuses on the art of ploughing and it gives our ploughmen and plough-women a wonderful opportunity to share their skills and demonstrate their expertise." she said.
"However, the event is much bigger than ploughing."
The event is taking place at Ratheniska, near Stradbally.
The Department of Agriculture and Rural Development's stand at the event features a number of diversified farming businesses, including crafts, engineering technology, services, tourism and food.
Now in its 83rd year, the first inter-county ploughing contest took place in 1931 to settle an argument between two friends from counties Wexford and Kildare.
The championships have since grown from a small field of 26 acres to 700 acres of land.
The event features tractor, vintage and horse ploughing.
As well as all-Ireland titles, those taking part will be competing to qualify for European and world competitions.