Tens of thousands of flood-hit North Korean families urgently need clean drinking water to prevent disease outbreaks, UN agencies said Thursday.

The agencies and other aid groups reported their assessment a day after state media reported a total of 119 deaths and major crop damage in recent weeks in the food-scarce nation.

The UN said wells have been contaminated by overflowing latrines, creating a high risk of a diarrhoea outbreak, while floods had damaged water sources and pumping stations.

Citing government figures, it said about 50,000 families in six badly-hit counties would need purification tablets or other help to secure clean water.

The UN children's fund UNICEF has ordered 10 million tablets along with other materials. Drugs and IV fluids were badly needed.

The report said a hospital in Chonnae county had already seen a fourfold rise in diarrhoea cases. "In general, unless... needs are addressed, rapid increase in diarrhoea, skin infection and respiratory infections could occur."

The North late Wednesday reported 31 killed by landslides and lightning during storms on Sunday and Monday and 16 missing, in addition to 88 earlier reported dead in floods and storms last month.

More than 21,000 people lost their homes in the latest storms, bringing the total made homeless by the recent bad weather to around 84,000, it said.

A total of 45,370 hectares (122,500 acres) of farmland had been submerged or washed away.

Coal mines in the Kaechon and Tokchon areas were also hit by "devastating" floods and tens of thousands of tonnes of coal and equipment was washed away.

The flooding represents a challenge for Kim Jong-Un, new leader of a nation which has grappled with severe food shortages since a famine in the 1990s killed hundreds of thousands.

UN agencies estimated last autumn that three million people would need food aid this year even before the deluge.

The UN report said it was difficult at present to assess the longer-term impact on food supplies, but any future floods in the cereal basket regions would hit food production more severely.

The International Federation of Red Cross and Red Crescent Societies (IFRC) said it would allocate 300,969 Swiss francs (almost $308,000) to cover the cost of immediate help for some 2,500 families.

Widespread deforestation, partly to clear land for crops, has made the impoverished nation increasingly prone to serious flooding which washes away the harvest.

IFRC regional spokesman Francis Markus, in an email to AFP, said the landslides were a reminder of the severe deforestation which the IFRC was trying to correct.

Millions of seedlings were planted every year under a programme which began several years ago.