South Korea today accepted an offer from North Korea to provide humanitarian assistance to victims of recent flooding. If delivered, it would be the first exchange of aid between the two bitterly hostile governments since the Korean War.

The South Korean Red Cross, announcing the acceptance, cited a desire "to pave the way for genuine, mutual and humanitarian assistance between fellow Koreans and to improve inter-Korean relations."

The North's offer of medicine, rice, cloth and cement, broadcast by its official radio six days ago, was in response to floods and landslides in the South that killed 139 people, left 200,000 homeless and heavily damaged crops.

There was speculation here that North Korea may have made the offer merely to score points in its propaganda war with the South and expected it to be rejected, as were two similar offers in 1959 and 1960. By this analysis, the North will now find reasons not to send the aid.

Similarly, the South may be accepting the offer with an expectation that the North will not come through, and thereby lose standing in the international arena.

The South Koreans asked that talks begin immediately with the North Korean Red Cross concerning details of transporting the goods. The North Korean news agency said the North agreed to meet and proposed starting the talks on Tuesday in Panmunjom, in the Demilitarized Zone between the two countries.

North Korea's aid offer followed other diplomatic moves that some analysts here feel represent a softening of its strategy toward the South. Their relations sank to an unusual low last year after a bomb blast blamed on North Korean agents killed four South Korean cabinet ministers and 12 other officials during a state visit to Burma.

Any discussion or exchange at all between Seoul and Pyongyang, the North Korean capital, is highly unusual. With an estimated 1.2 million troops massed against each other along the Demilitarized Zone, they maintain the most hostile relationship possible short of open war. About 30,000 U.S. troops are stationed in South Korea.

Western and Japanese analysts here called the aid move significant. "It seems to be a sign the North is interested in at least taking superficial measures to reduce tension," said one western diplomat here.

South Korean President Chun Doo Hwan has just returned from an official trip to Japan, the first by a Korean head of state. Since coming to power in 1980, he has been promoting an image of aggressive, humanitarian diplomacy in a flurry of visits to Asia, Africa and the United States.

Pyongyang has made two other moves in recent months that some analysts here interpret as conciliatory. One was its proposal for "three-way" talks between it, the United States and South Korea to find a political settlement to the peninsula's problems. In some views, that proposal softens the North's position that the South is a puppet of the United States and not worthy of a role in discussions.

In addition, the North this week announced a new law to permit foreign companies to invest in joint ventures in North Korea. Although little response is expected from business, the step has been called an opening toward the outside.

The signs have not all been positive, however. Preliminary discussions between the two governments' Olympic committees broke down earlier this year in a storm of name-calling. And the North rejected an offer from Chun in August for technological aid.

The political nature of the disaster assistance was underlined today when the South Korean Red Cross noted that most of the flood damage already had been repaired and that it had rejected as unnecessary an offer for help from the International Committee of the Red Cross.

In its radio broadcast last week, the North proposed giving the South medicine, 50,000 sacks of rice, 550,000 yards of cloth and 100,000 tons of cement. They could go either by ship or truck, it said.

The South Korean Red Cross' response, which came in close consultation with the South Korean government, asked that the commodities be sent by ship either to the port of Inchon, 20 miles west of Seoul, or to Pusan, at the southern tip of the peninsula.

Concerns that large numbers of North Korean trucks crossing the Demilitarized Zone would cause security problems were apparently behind the South's request for sea shipment.