China has banned pork imports from Poland, a leading EU exporter of the meat, after Warsaw confirmed its first two cases of African swine fever among wild boars.

China is home to half of the globe's pigs, and the United Nations' Food and Agriculture Organisation (FAO) has warned of "vast losses" should the swine fever take hold there.

The Chinese measure comes after Russia slapped its own ban on pork imports from the 28-member European Union after the disease appeared in Lithuania, a move Brussels criticised as "disproportionate".

"China has informed the European Commission of a ban on Polish pork imports," Poland's agriculture ministry spokeswoman Malgorzata Ksiazyk told AFP on Thursday, without specifying when the ban took effect.

The minister, Stanislaw Kalemba, met China's ambassador to Warsaw Xu Jian last week to explain the measures Warsaw was taking to prevent the spread of the swine fever (ASF) on its territory, she added.

ASF is harmless to humans but lethal to pigs and has no known cure, posing a grave threat to commercial pig farms. The disease has not been detected in Polish pigs, only wild boars.

State veterinarians confirmed ASF in Poland last week following tests on the carcasses of wild boar found near the village of Szudzialowo, just under a kilometre (mile) from the border with Belarus.

The disease has spread throughout the Balkans, the Caucasus and Russia since 2007, and is endemic to areas of Africa, according to the FAO.

China is the largest importer of Polish pork, having absorbed 52,000 tonnes in 2013 worth 68 million euros ($92 million).

A leading pork player in the European Union, Poland exported 912 million euros worth of the meat last year.

A buffer zone has been created along parts of Poland's eastern border with Belarus, Lithuania and Ukraine as part of Warsaw's efforts to contain the spread of ASF.

Officials have ordered farmers to fence in their land, lay down disinfectant mats and test and monitor shipments of live pigs out of the zone.

Moscow banned pork imports from the EU on January 29, after Lithuania confirmed the disease in two wild boars.

Russia buys a quarter of the bloc's pork exports, worth around 1.4 billion euros annually.