By Jack Kim

SEOUL, Dec 12 (Reuters) South Korea's demands that the United States change its anti-dumping laws could wreck chances of pushing through a free trade agreement, U S Commerce Secretary Carlos Gutierrez said today.

The issue was a major obstacle in the latest round of negotiations last week on a trade deal between the United States and Asia's third-biggest economy.

''We have a mandate from Congress to carry out Free Trade Agreements (FTA) without changing our dumping laws,'' Mr Gutierrez told reporters during a visit to the South Korean capital.

''And we have a serious concern that if we request the change to those laws, that could be something that stops or jeopardises the approval of the free trade agreements.'' An agreement would be the biggest US free trade deal for more than a decade and needs approval by Congress, many of whose members see anti-dumping as vital protection against unfair trade practices. Seoul however believes such measures are often unfairly applied to its products.

The two countries are striving to reach a free trade agreement by early next year.

Gutierrez also urged South Korea to show goodwill by fully opening its market to US beef.

''American beef does not enjoy any real access,'' he told businessmen. ''We simply cannot convince the US people or our Congress that an FTA is a good idea if it is not a fair deal.'' The South Korean government, which only just allowed imports of US beef back after a three-year ban because of mad-cow disease concerns, rejected the first three shipments after finding fragments of bone.

The rejection has infuriated US cattle producers and senior officials, who accuse Seoul of inventing reasons to keep its beef market closed.

In turn, South Korean farmers have violently protested the resumption of imports, saying it threatened their livelihoods.

In last week's trade talks in the United States, already well behind schedule, the two countries clashed over several issues, which also included Seoul's barriers to auto imports.

Underscoring the divide, a senior South Korean official said Seoul could break off negotiations if Washington pressed it to open its rice market.

''Rice should be excluded from a free trade pact with the United States,'' Bae Jong-ha, a director at the agriculture ministry, said.

South Korea heavily protects its rice farmers but at a cost to local consumers who pay four times more than their U.S.

counterparts.

South Korea is the United States' seventh-largest trading partner and seventh largest export market, with trade between the two countries worth 72 billion dollars in 2005, the Commerce Department said.

REUTERS SHB HT1437