Grain demand in Japan, the world's largest corn importer, is unlikely to decline even after Friday's earthquake and tsunami damaged some of the nation's ports and disrupted deliveries, the United Nations said.

The country, struck by its strongest earthquake on record Friday, faces power blackouts and the increasing danger of radiation leaks at a crippled nuclear facility. The unloading of U.S. corn from vessels at Kashima and other northern ports was suspended because of power outages, Zen-Noh, Japan's largest corn buyer, said Monday.

"I don't see any particular reason for demand to decline at the moment," Hiroyuki Konuma, Asia's regional representative at the U.N.'s Food & Agricultural Organization, said from Bangkok. "Ports in the northern part aren't major ports. For importing foods from abroad, shipments can be redirected to other ports. Demand remains there."

Sustained purchases by Japan may help push corn prices higher, after futures in Chicago slumped to the lowest level in almost two months Tuesday. Prices have tumbled 13 percent this month.