Pigs raised by farmers are seen at Linquan county on December 5, 2018 in Fuyang, Anhui Province of China.

China has asked pork processors and pig dealers to obtain certificates proving their products are free from African swine fever, state news agency Xinhua reported on Wednesday.

The disease has spread rapidly in the world's biggest producer and consumer of pork, reaching every province on the Chinese mainland since its initial detection there last August.

"Processors and dealers should have all pork products examined for the swine fever virus," Xinhua said, citing a government notice.

It was unclear who would conduct the examinations or issue certificates, but the notice was jointly issued by the State Administration for Market Regulation, the Ministry of Agriculture and Rural Affairs and the Ministry of Industry and Information Technology.

The order takes effect from Wednesday, with violators facing "harsh" punishment, the report said.

More inspections of markets, traders and restaurants have also been ordered, according to the report.

African swine fever kills almost all pigs infected, though it is not harmful to people. There is no vaccine or cure.

China's pork output fell 5.2 percent in the first quarter of 2019 compared with a year earlier, according to official data issued last month.