Irish Prime Minister Enda Kenny told CNBC on Wednesday that the process of the United Kingdom leaving the EU is likely "the most difficult economic issue of the last 50 years."
"We have a great relationship with the United Kingdom, trade of [1.2 billion euros or $1.3 billion] across the Irish Sea every week," the prime minister said on "Squawk on the Street."
"But when U.K. leaves, Ireland will be the only country with a land border internal to the European Union. It brought with it sectarian violence and troubles. We don't want to go back there and we are not going back there," he said.
Kenny's comments came after British Prime Minister Theresa May cleared the final hurdle standing between her and the start of Brexit negotiations after Parliament passed legislation giving her the power to start the EU exit process.
"We are now on the threshold of the most important negotiation for our country in a generation," David Davis, the U.K. minister responsible for Brexit negotiation, said in a statement
On Thursday, Kenny will meet with President Donald Trump as part of a tradition between the two countries during the week of St. Patrick's Day.
The trip has caused some controversy in Ireland, with many in the media and broader public claiming that it should have been canceled in defiant response to Trump's temporary ban on travelers from six majority-Muslim countries.
The prime minister, who has called Trump's language "dangerous and racist," said Wednesday the meeting is not about "me or the president."
"This is a tradition that's gone back very many years enhanced by Tip O'Neill and Ronald Reagan many years ago," he said. "It's about symbolic contribution that the Irish made to America over 250 years and we'll continue to make."
— Reuters contributed to this report.