BEIJING (REUTERS) - China's agriculture ministry said on Wednesday (Oct 24) it was banning the feeding of kitchen waste to pigs after linking the practice to the majority of the early cases of African swine fever.

The statement from the Ministry of Agriculture and Rural Affairs is the government's first comment on how the deadly disease has spread in the world's top pork producer.

China has reported more than 40 outbreaks of the highly contagious disease since early August, with farms across 12 provinces and municipalities already infected.

Beijing has not yet said how the disease first entered the country but the ministry found 62 per cent of the first 21 outbreaks were related to the feeding of kitchen waste, according to a statement published on its website.

"These outbreaks were mostly located in urban-rural boundaries, and were particularly evident in several cases in early September in Anhui province," the statement said. Anhui is an eastern province whose capital Hefei is located about 415km west of Shanghai.

The virus was also detected in kitchen waste fed to pigs on a farm in the Inner Mongolia region, it added.

"After the provinces with outbreaks and neighbouring provinces completely banned feeding of kitchen waste to pigs, the epidemic was greatly reduced, which fully demonstrates the importance of completely prohibiting the feeding of waste," the statement said.

Kitchen waste or swill is widely used in China to feed hogs, particularly by small farmers, as it is cheaper than manufactured pig feed.

Regulations require that the swill must be heated to a certain temperature before being consumed but industry experts say that step is often skipped.

The ministry also said in the statement that it will set up a registration system for vehicles transporting live hogs, poultry and other livestock to better control the spread of the disease.

The long distance transport of live hogs has been the main channel for transmitting African swine fever across different regions, it said.