* Pact faces more hurdles in South Korea
* Obama admin. says working on implementing two other pacts (Updates with US industry, lawmaker comments)
SEOUL/WASHINGTON, Feb 21 (Reuters) - A long-delayed free trade deal between the United States and South Korea will go into effect on March 15 following months of technical-level talks, officials said on Tuesday, cheering business groups that have waited years for the day.
The pact was signed nearly five years ago but faced tough resistance from some industry and agricultural interests in both countries. It may face still more hurdles in South Korea, where the opposition party has said it will try to repeal it.
South Korea's Minister for Trade Park Tae-ho told reporters implementation of the deal would help South Korean exporters who have lost sales to Europe because of that continent's debt crisis that has hurt consumer and business demand.
"Coming at a time such as this, the U.S. free trade agreement is a positive opportunity for our exports to the United States, which is the world's largest developed market, to grow significantly," he said.
U.S. Trade Representative Ron Kirk, in a statement issued in Washington, said the pact will help support tens of thousands of American jobs in export industries.
"Entry into force of this agreement will open up Korea's $1 trillion economy for America's workers, businesses, farmers, and ranchers while also strengthening our economic partnership with a key Asia-Pacific ally," Kirk said.
U.S. business groups, including the U.S. Chamber of Commerce and the National Association of Manufacturers, applauded news of the implementation, which follows months of detailed technical talks to ensure each side has made all the legal and regulatory changes required under the agreement.
The National Cattlemen's Beef Association said the agreement, which phases out South Korea's tariffs on U.S. beef over 15 years, "may very well be the most monumental bilateral trade pact our industry has ever witnessed."
Meanwhile, Representative Dave Camp, Republican chairman of the House of Representatives Ways and Means Committee, urged President Barack Obama's administration to also bring two other long-delayed trade pacts with Colombia and Panama into force "as quickly as possible."
Congress passed all three agreements in October.
The Obama administration has said it is working to implement the two Latin American deals as soon as possible, but has not given a precise timetable for that.
The U.S.-South Korea deal will eliminate Seoul's duties on almost 80 percent of U.S. industrial products and almost 67 percent of U.S. farm goods on its first day of entry into force.
Commitments opening up South Korea's $580 billion services market also take effect beginning March 15.
South Korea's parliament, currently controlled by the ruling conservatives, approved the deal in November amid rowdy scenes of opposition lawmakers protesting, after it was signed in 2007 by the then-government of left-leaning President Roh Moo-hyun.
Though it was the opposition that initiated the free trade agreement when it was in power, its legislators argue that subsequent changes to allow U.S. carmakers a major inroad into the market and a dispute settlement mechanism will strip South Korea of any ability to defend its interests.
Jeffrey Schott, a senior fellow at the Peterson Institute for International Economics in Washington, said he doubted opposition candidates would make good on their threat to repeal the pact, even if they win parliamentary elections in April and a presidential election later this year.
"I think it's electoral rhetoric. Implementing the exit clause is costly in both economic and political terms. I think any responsible leader in South Korea would be very reluctant to touch it," Schott said.
Kirk said Obama's insistence on renegotiating the agreement to get more favorable auto provisions for the United States was the reason it was approved with "strong bipartisan support" in both the U.S. Senate and House.
The two countries signed off on changes to the auto provisions in December 2010, setting the stage for Obama to finally submit the pact to Congress for approval more than 2-1/2 years after taking office.