North Korea is seeking international help after it reported massive flooding had left hundreds of people dead or missing and washed away many buildings, a U.N. aid agency spokesman said on Tuesday.

North Korea, which has struggled with chronic food shortages for years, also said in a report early on Tuesday that floodwaters caused "tens of thousands of hectares of farmland (to be) inundated, buried under silt and washed away."

Pyongyang has been badly hit by flooding.

Paul Risley, Asia spokesman with the U.N. World Food Programme, said: "If the figures are borne out by our own assessment, then we are very concerned that this is a significant emergency crisis."

"It is still very early in this process but we have received a preliminary request from North Korean authorities, asking for our assistance," Risley said.

He said an inter-agency relief team was expected to be in North Korea in the next day.

Three big storms hit North Korea in 2006, and a pro-Pyongyang newspaper reported that more than 800 people were killed or went missing in the resulting floods. The damage figures North Korea reported last year were lower than for this year's flooding.

South Korea's Unification Ministry said on Tuesday it expected damage to be worse than last year. The International Federation of Red Cross and Red Crescent Societies said it is on 24-hour alert to monitor damage.

A unification ministry official said the government was looking into possible flood aid for North Korea but had not received any request from Pyongyang.

The floods were not expected to affect a planned leaders' summit between the two Koreas on Aug. 28-30, he added.

North Korea's official KCNA news agency said at least 800 public buildings and more than 540 bridges had been washed away, while sections of railroad had been destroyed and thousands of homes ruined.

The communist state's infrastructure outside of showcase places in the capital Pyongyang, is mostly a shambles. North Korea has few funds for building and still uses power and rail lines built during Japan's 1910-1945 colonial rule.

The flooding has hit most of the southern half of North Korea and includes the capital and some of its most productive agricultural regions.

North Korean passersby make their way through a flooded street in Pyongyang, North Korea, Tuesday, Aug. 14, 2007 , in this image made from television.

Years of mismanagement of the farming sector mean the country does not produce enough food to feed its nearly 23 million people. Famine in the mid-to-late-1990s might have killed up to 10 percent of the population, experts have said.

Even in a good year, North Korea still falls about 1 million tonnes short of the food it needs to feed its people.

The WFP is the main international aid agency on the ground in North Korea trying to feed the country's poor. (With additional reporting by Jack Kim)