BEIJING (AFP) -- China ordered its farmers to ramp up food production Thursday following days of rising prices, with agricultural supplies disrupted by a deadly viral outbreak.

The government in Beijing has taken extraordinary steps to combat the spread of the new coronavirus, restricting transport across the country and effectively locking down more than 50 million people in Hubei province, the epicentre of the disease.

But officials said some local initiatives, such as roadblocks to stop travel between provinces, had also obstructed produce supply chains.

"This has caused vegetables and other products... to be unable to leave the villages and reach cities, as well as difficulty in replenishing the feed for livestock and poultry in time," the agriculture, transport and public security ministries said in a joint statement.

It said feed producers should "speed up" production to meet demand for animal feed, and slaughterhouses needed to "increase the effective supply of livestock and poultry products".

The notice came as the China Shouguang vegetable price index, a daily benchmark of national produce costs, surged to its highest level in almost four years, Xinhua News Agency reported.

Food prices were already under pressure after African swine fever raced through the country's pig herds, pushing up pork prices by 97 percent on-year in December.