South Korea is sending the first dispatch of relief supplies including 5,000 tons of rice to North Korea on Monday, after it was battered by torrential rain in summer 2010, officials said.
Two ships carrying rice and instant noodles were to depart South Korean ports for the northeastern Chinese port of Dandong on the border with North Korea, the South's unification ministry said.
The aid will be delivered later from Dandong to the North's border city of Sinuiju, it said.
South Korea has promised to send a 10 billion won (8.3 million dollars) aid package including rice, instant noodles, cement and other emergency supplies.
Monday's shipment marks the South's first government-financed rice aid to its impoverished neighbour since a conservative government took office in Seoul in early 2008.
Cross-border relations have been icy since Seoul accused Pyongyang of torpedoing a South Korean warship in March with the loss of 46 lives.
The North denies responsibility but has made some peace gestures. This weekend the two sides will resume reunions of families separated by war 60 years ago.
In August, heavy rain devastated the North's northwestern region.
Typhoon Kompasu, which hit the peninsula in early September, further battered North Korea, killing dozens of people and bringing more damage to the nation, which is vulnerable to flooding after years of deforestation.
Aid groups warned that 2010's flooding would aggravate the North's chronic food shortages.
But Seoul has been cautious in sending large-scale rice aid to the Pyongyang amid questions over whether the food will reach flood-stricken civilians or be diverted to feed the North's 1.2 million-strong military.
The ministry said rice would be delivered in packs marked with "Donation from the Republic of Korea", the South's official name.
The South used to ship 400,000 tons of rice a year plus 300,000 tons of fertiliser to the North, but the shipments ended in 2008 as Seoul adopted a harder line towards Pyongyang.