Traders found hoarding rice while the country struggles to maintain sufficient stocks of its staple grain could be charged with economic sabotage, a crime that carries a life sentence, the justice secretary said Thursday.

Government agents have been raiding warehouses in a hunt for unscrupulous traders and warehouse owners holding on to rice stocks amid spiraling prices and fears of a shortage, Justice Secretary Raul Gonzalez said.

The amount of rice hoarded and the resulting effect on the country's economy would determine whether economic sabotage charges could be filed, Gonzalez told The Associated Press.

He said 111 warehouses, each holding at least 40,000 sacks of rice, have been found in northern Bulacan province. A justice department task force was investigating whether any of those facilities had hoarded grains.

President Gloria Macapagal Arroyo has vowed to crack down on rice hoarders, ordering the arrest of those who buy subsidized rice from the government to sell later at a higher price.

Rice prices have jumped 50 percent in the past two months on world markets and at least doubled since 2004. Experts blame rising fuel and fertilizer costs as well as the effect of disease, pests and climate change on crops. Farmers' groups have warned that prices could rise a further 40 percent in coming months.

The higher prices have already sparked protests in the Philippines, where a government official has asked the public to save leftover rice and communist rebels have vowed to take advantage of the situation to stir up public unrest.

The Philippines' 90 million people consume about 13.1 million tons of rice annually, most grown domestically. But dwindling domestic production and corruption in the rice supply chain have created a recurrent shortfall of about 10 percent.

The government has to purchase at least 2.2 million tons from the international market every year, making the Philippines the world's biggest rice importer.