UN food agencies have begun a mission to North Korea to assess the food security situation after a particularly harsh winter and amid a sharp rise in global food prices, UN officials said on Friday.

The mission comes after a visit by the World Food Programme (WFP) and the Food and Agriculture Organisation (FAO) last year that found that an estimated five million people in the secretive state face food shortages in 2011.

"We have a joint food assessment mission with the Food and Agriculture Organisation (FAO) which started yesterday and is to continue until March 6," said Greg Barrow, a spokesman for the Rome-based World Food Programme (WFP).

A UN official, speaking on condition of anonymity, said the mission could lead to the launch of a WFP emergency operation in April to help millions of people at risk of hunger, including children and mountain region residents.

The mission follows a formal request from North Korea and will review the secretive state's "short-term food security... in view of the government's stated inability to import as originally thought," the official said.

The last WFP emergency operation for North Korea lasted between September 2008 and November 2009 and was the UN agency's biggest international operation ever, with more than six million benefiting from food assistance.

Barrow said that the mission would look into the impact of "a particularly harsh winter" in North Korea this year and the sharp rise in global food prices, which the FAO said hit their highest ever level last month.

North Korea, which suffers from regular severe food shortages, this week said it has also been hit by an outbreak of the highly contagious foot-and-mouth disease and that thousands of animals have died.