Korea's main opposition party on Saturday called on the government to ban U.S. beef imports following the discovery of a new mad cow case.

Democratic United Party (DUP) chief policymaker Lee Yong-sup said in a news conference that the government broke its promise to the people to stop imports if another case of bovine spongiform encephalopathy (BSE) is discovered in the United States. BSE is the official name for brain-wasting mad cow disease that can be transmitted to humans and cause the fatal variant Creutzfeldt-Jakob disease.

"Instead of keeping its word, Seoul has only moved to tighten quarantine inspections whose effectiveness is questionable," he said.

He said since Washington confirmed the latest BSE case, Seoul should halt quarantine inspections and ban all imports of beef from the United States.

The DUP lawmaker said that there are no obstacles to the government stopping imports.

"All that is needed is the will of the government," he claimed, arguing that using loopholes in existing regulations to not take positive action is irresponsible.

He said if the government continues to ignore its obligations to protect the health of the public, the National Assembly could take steps to revise existing laws that will strengthen the current import health requirement act.

Lee's announcement comes a day after ruling Saenuri Party interim chief Park Geun-hye urged the government to stop quarantine inspection on U.S. beef.

The leading candidate for the ruling camp in the upcoming presidential race said U.S. beef imports need to be halted until there is confirmation that eating the meat is safe.

The government, meanwhile, said while it will provide detailed information on the latest BSE case, it has no immediate plans to stop quarantine inspections.

Preventing beef from clearing quarantine effectively stops the meat from reaching consumers, although the step does not ban imports outright. Any imported beef will be kept in cold storage.

The latest mad cow case reported is the fourth to be detected in the U.S.

Seoul had banned U.S. beef imports in late 2003 after the first case was reported, but fully reopened the market in 2008 after long-drawn negotiations with Washington.

In 2011, South Korea brought in 107,000 tons of U.S. beef or 37 percent of all imports that year, with 28,000 tons purchased last month.(Yonhap)