Seoul: Floods that swept across North Korea earlier this month left at least 600 people dead or missing, the country's official news agency said - double the previously reported toll.

Citing North Korea's Central Statistics Bureau, the Korean Central News Agency reported on Saturday at least 600 people were dead or missing, and thousands more injured.

Earlier, international aid groups had put the toll at about 300 dead or missing.

KCNA said the heavy rains caused "huge material losses" to the country, "creating unprecedented difficulties in people's living and economic construction".

North Korea's Agriculture Ministry said the devastating floods damaged more than 20 per cent of the country's rice paddy and 15 per cent of its corn-growing areas, the UN Office for the Coordination of Humanitarian Affairs said in a statement posted on its website on Saturday.

The North had previously said the storms destroyed more than 11 per cent of its crops.

The UN office also cited North Korean Government figures saying the floods have displaced 169,561 people.