United Nations Secretary General Ban Ki-moon has ordered a full evaluation of the needs of North Koreans following severe flooding in the country.
Mr Ban said he had asked UN teams to assess the damage, and promised assistance to the communist nation.
North Korea says hundreds of people have been killed in the floods, which were triggered by seasonal heavy rains. Large swathes of farmland have been destroyed, and North Korea has appealed to the UN food agency for help.
Experts fear flood damage to crops could lead to further food shortages in the impoverished nation.
About two million people are thought to have died from famine in the mid-1990s in North Korea, and the country remains dependent on foreign food aid.
'Very extensive'
Mr Ban held a meeting with North Korea's envoy to the UN, Pak Gil-yon.
"I assured him that the United Nations will be prepared to render whatever possible humanitarian assistance and help the DPRK (North Korean) government and people overcoming this difficulty," he said.
The US and South Korea have both said that they would consider sending aid.
Teams from agencies including the World Food Programme (WFP) and the World Health Organization are already assessing the damage inside North Korea.
"Our understanding is that the damage is very extensive," Paul Risley of the WFP told the BBC.
He said the floods were affecting a greater area than ones that struck a year ago. Hundreds of people are thought to have died in floods in August 2006, although exact figures are not known.
Ewa Eriksson of the International Federation of the Red Cross said that the agency had begun distributing relief supplies. She described the situation as "very serious".
North Korea announced late on Monday that storms since 7 August had led to "huge human and material damage".
State news agency KCNA said hundreds of people were dead or missing, while more than 30,000 houses had been destroyed.
Roads, energy infrastructure and arable land had been hard-hit, the agency said.
The three provinces of Kangwon, North Hwanghae and South Hamgyong provinces were the most affected, it said.
Television pictures from the capital Pyongyang showed people wading along streets through thigh-deep water after rivers burst their banks.
State news agency KCNA said hundreds of people were dead or missing, while more than 30,000 houses had been destroyed.
Roads, energy infrastructure and arable land had been hard-hit, the agency said.
The three provinces of Kangwon, North Hwanghae and South Hamgyong provinces were the most affected, it said.
Television pictures from the capital Pyongyang showed people wading along streets through thigh-deep water after rivers burst their banks.