A disease that has killed 18,000 pigs and helped send pork prices soaring in China is likely to get worse, the government said Tuesday, as it called for a vaccination drive to stem the epidemic, reported the Associated Press.

Over 45,000 pigs have been hit by the highly pathogenic "blue-ear disease" between January and May, even before the peak season of the summer and fall has started, the Ministry of Agriculture said on its website.

The ministry urged animal medical factories to produce more vaccine, while ordering local veterinarian stations to implement vaccination and disease control measures. The ministry also banned the sale and transport of sick pigs.

Prices of live pigs jumped 71.3 % in April nationwide while pork, an essential ingredient in a vast range of staple Chinese dishes, rose 29.3 %, state media reported earlier, quoting Ministry of Agriculture figures.

The rise in prices prompted Prime Minister Wen Jiabao to personally step in and call for measures to ensure pork supplies, while warning that rising costs for the staple meat could lead to social instability.

"We have noticed the recent rise in pork prices and the government is going all out to ensure the supply of pork and keep it affordable," Wen said in late May.

The ministry did not say which areas of China were being worst hit by the pig disease, but hundreds of pigs succumbed to the disease in south China's Guangdong province in April, triggering panic among breeders and buyers in the region.

"The outbreaks have contributed to rising pork prices in some areas," Xinhua news agency said Tuesday.

"It is believed the price hikes will help raise the country's consumer price index, or CPI, to a new high for May."

High grain prices, rising demand and low prices for pork last year, were also seen as contributing to higher prices, earlier press reports said.

China's consumer inflation rose three % in the first quarter over the same period last year, while food prices were up 7.1 % in April year-on-year, according to the National Bureau of Statistics.

China is the world's biggest pork producing nation, producing, slaughtering and consuming up to 50 % of the world's annual pig harvest.

In 2002, China raised 457 million of the world's 939 million pigs, according to the UN's Food and Agriculture Organisation.