Quarantine officials will join hands with food safety authorities to clamp down on illegal distributions of banned livestock products sold online and offline and inspect local hog farms to check if they feed unprocessed food waste to pigs, the ministry said.

The Seoul government attributed the rapid spread of pig virus in China to use of improper animal feed, illegal distribution of infected pigs and lax inspection on local hog farms.

"African swine fever is spreading across China," the ministry said. "Considering the virus was detected in processed pork products, the ASF outbreak seems serious."

China has culled more than 24,000 pigs in four provinces to try to stem the spread of the disease.

The rising number of swine fever cases has raised fear in South Korea as China produces almost 700 million pigs a year, or about half of the world's total.

There is no effective vaccine against African swine fever, whose fatality rate is 100 percent. The disease poses no direct threat to human health, according to the UN Food and Agriculture Organization.

The virus is very hardy and can survive long periods in very cold and very hot weather, and even in dried or cured pork products, it said. (Yonhap)