North Korea has reported widespread damage to homes, railways and roads following heavy rains that battered the nation last week, in a rare admission of problems within the reclusive country.

"Officials and working people in various parts of the country have turned out as one in the relief and rehabilitation activities," the official Korean Central News Agency said.

"A large acreage of land under cultivation" has been washed away or buried, with roads, railways, houses and public buildings destroyed, it added.

The agency gave no figures on damage or casualties. Last year monsoon rains swept through much of the impoverished nation, killing hundreds of people.

It said that the communist government had taken "every possible measure" to ensure supplies to help the affected areas.

Experts say decades of reckless deforestation have stripped North Korea of tree cover that provides natural protection from catastrophic flooding.

Energy-starved residents have used every scrap of wood from the countryside to cook food or heat homes through the bitter winters, leaving large areas of the country vulnerable to flooding and landslides.

Government officials have worsened the problem by encouraging residents to expand farmland into the hillsides in a bid to grow more food.