GOFFSTOWN — Han Duk-soo, South Korean ambassador to the United States, stopped by St. Anselm College and the New Hampshire Union Leader on Monday during his cross-country tour to promote a free trade agreement between the U.S. and the Republic of Korea.

If passed, the agreement would eliminate about 95 percent of tariffs between the two countries and mark the largest free trade agreement for the United States in 17 years since the implementation of the North American Free Trade Agreement.

“It will help a lot of companies grow in New Hampshire and the United States,” Han said.

New Hampshire exports to South Korea increased 188 percent from 2009 to 2010, bringing in $131 million. The Granite State was ranked the third highest in the nation in exports last year.

Han, who is the Republic of Korea’s former prime minister, said an agreement would strengthen the business relationship with South Korea, the world’s 15th largest economy.

“The U.S. used to be Korea’s largest trading partner but lost that distinction to China in 2004,” Han said, adding that Korean tariffs cost U.S. businesses $13.2 billion last year.

“Trade agreements ... level the playing field for American companies,” said Tammy Overby of the U.S. Chamber of Commerce, who accompanied Han and a handful of associates to St. Anselm, then on a tour of the Union Leader and a brief visit with editors at the newspaper.

The free trade agreement, known as KORUS, was signed by leaders in South Korea and the U.S. in June 2007, but has yet to be ratified.

Supported by President Barack Obama and former President George W. Bush, the agreement would add more than $10 billion to the annual U.S. Gross Domestic Product and another $10 billion to annual merchandise exports to the Republic Korea, according to White House officials.

Despite support from top leaders, there has been opposition from groups of lawmakers in both Korea and Washington, D.C., in recent months.

U.S. Rep. Brad Sherman, D-Calif., last month asked fellow congressmen to reject ratification of KORUS, saying in a statement “nothing in this agreement prevents (imported products) from being North Korean.” Communist dictator Kim Jong-il leads North Korea, the Democratic People’s Republic of Korea.

South Korean media reported this month that some opposition party lawmakers there don’t want to ratify KORUS because they fear an imbalance of trade benefits.

“I feel regretful KORUS still isn’t ratified... Time is running out,” Han said Monday. “It will help a lot of companies grow.”

U.S. Rep. Charlie Bass, R-N.H., opened Monday’s breakfast speech at the college, saying he supports creating free trade after his four visits to the Asian republic since the 1990s. Bass said one in four New Hampshire jobs is dependent on foreign exports.

“The economies around the world these days are fragile but can be strengthened through free trade,” Bass said. “Having a good, strong relationship with South Korea is critical.”

Han said an agreement could save 280,000 jobs in the U.S. Some lawmakers have been skeptical of that, including U.S. Rep. Louise Slaughter, D-N.Y., who voiced skepticism recently about KORUS and its intention.

“This trade pact was written by a Republican administration with the corporate bottom line in mind,” she said.