South Korea’s top negotiator in talks on a free-trade agreement with the United States offered reassurances Friday that his government will ratify the long-stalled deal by the end of the month, shortly after its expected approval in Washington.

Kim Jong-hoon, the South Korean trade minister, said in an interview at his office that Seoul will ease domestic concerns about the pact in much the way the United States has — by attaching an assistance program for workers hurt by foreign competition.

Congress is poised to approve the agreement next week. But South Korea is several steps behind the United States: It must still send the agreement to its legislature, and it must also contend with the opposition Democratic Party’s demands for broad revisions that would force negotiators back to the table.

Kim said Friday that once the United States approves the deal, which the Obama administration projects would increase U.S. exports by up to $11 billion, it will be “just a matter of days, at the very longest just a matter of weeks,” before South Korea follows.

“It is too early yet to raise any glass of congratulations,” he said. “But we are very close to the final line.”

Some of the opposition’s concerns are well founded, observers here say, with Korean farmers and small-business owners likely to lose ground as U.S. products flood the market. But Kim said the proposed spending program to help those groups, similar to the U.S. trade assistance program, would address at least some of their misgivings, and he voiced impatience with the Democratic Party’s resistance.

“We are now in the final phase,” he said. “If we look for changes, it will take a long, long time. We may never get to the end.”

South Korea’s ruling Grand National Party holds a strong enough majority to guarantee passage of the agreement. But a boisterous opposition could spark subsequent problems, including protests and increased anti-American sentiment.

The push for the deal has gained momentum at an opportune time, especially in Washington, where President Obama is seeking new ways to mend the U.S. economy and South Korean President Lee Myung-bak is scheduled to visit next week. The pact, signed in 2007, would remove 95 percent of existing tariffs within five years and give U.S. exporters, particularly in the agriculture and automaking sectors, better access to the South Korean market.

As the deal languished in recent years, held up by new administrations in both countries and a two-year renegotiating session, South Korea sought other trade partners, doubling its business with China and signing a free-trade deal with the European Union. Seoul has nurtured the world’s 12th-largest economy largely with its aggressive pro-trade moves — something that Kim says will not change as the global economy slows. The country has 19 pending or proposed free-trade agreements, including one with China.

“We are now naturally thinking about when would be good timing” to begin more formal talks with China, Kim said.

The U.S.-South Korea pact, if approved, would be South Korea’s eighth such deal.

Business leaders and automobile manufacturers here back the agreement. But farmers are wary. U.S. agriculture products, on average, face 49 percent tariffs in South Korea — fees that would largely disappear under the deal. A 40 percent tariff on beef, for instance, would be phased out over 10 years, allowing U.S. beef to regain some of the share it lost in the mid-2000s amid a global scare about mad cow disease.

During that time, beef concerns alone threatened the free-trade deal, and protesters thronged Seoul’s Trade Ministry building. “Every traffic stop was blocked,” Kim said. “I couldn’t even get home.”

South Korea reopened its markets to U.S. beef three years ago, and the product has since crept back onto shelves here. But once the tariff is removed entirely, costs for U.S. beef will drop $1,300 a ton, boosting its appeal to a middle class increasingly pinched by education costs.

South Korean farmers have cause to feel vulnerable to such competition, Kim acknowledged.

“Their land is very small” compared with a cattle ranch in Montana or Texas, he said. “So they need some government support to modernize. That’s a major part of this expenditure” on trade assistance.

Special correspondent Yoonjung Seo contributed to this report.