South Korea said it would provide aid beginning with an initial package that will total $7.5 million in relief supplies.
U.S.-based relief organization Mercy Corps said it planned to provide some $500,000 in food, medicine, clothes and tools to North Korea after discussing the situation with its counterparts there.
Japan also said it would consider giving aid if asked by North Korea, but it did not yet have specific plans.
The North Korean government granted the World Food Programme permission to send four emergency teams Friday to stricken areas, providing a wider independent assessment of the damage.
A senior U.N. official in New York said 58,000 homes had been destroyed along with nearly 222,400 acres of farmland, leaving 300,000 people homeless. U.N. Assistant Secretary-General Margareta Wahlstrom, deputy emergency relief coordinator, said 83 people were dead and about 60 missing.
The U.N. said its relief officials in the region reported floodwaters had wrecked more than 800 public buildings, 540 bridges, 70 stretches of railway and more than 500 electricity towers. More than 30 water reservoirs and 450 agricultural structures were damaged, it said.
The series of unusually detailed official reports on the disaster were viewed as a public cry for help from the government, which is usually extremely reluctant to reveal any signs of internal trouble to the outside world.
However, North Korea has a history of overstating the effects of disasters to get aid.