More than a thousand homes were damaged and some 5,000 people have been evacuated after flooding caused by heavy rains in North Korea, the country's state broadcaster reported, with swathes of farmland also inundated by the deluge.

The TV report comes as the impoverished North in June admitted it was tackling a food crisis, sounding the alarm in a country with a moribund agricultural sector that has long struggled to feed itself.

Last month, the UN's Food and Agricultural Organisation forecast said North Korea was facing a food shortage of around 860,000 tonnes this year, warning the country could experience a "harsh lean period".

Footage from Pyongyang's state-run KCTV showed homes flooded up to their roofs, as well as what appeared to be damaged bridges.

The report said that "hundreds of hectares of farmlands" were also submerged or lost in the country's South Hamgyong Province, on top of the severely affected homes and roads, as river levees collapsed.

Natural disasters tend to have a greater impact on the isolated country due to its weak infrastructure, while deforestation has left it vulnerable to flooding.

A series of typhoons last summer also triggered floods that damaged farmland and destroyed thousands of homes.

Leader Kim Jong Un said in June the country's food supply situation was "getting tense" due to the lingering typhoon damage, and called for steps to minimise the impact of natural disasters.

North Korea is now under self-imposed isolation to protect itself against the coronavirus pandemic, and as a result trade with Beijing -- its economic lifeline -- has slowed to a trickle.