A North Korean proposal for talks this year with South Korea is being studied closely for signs that the Communist government is now willing to discuss reunification of the country, which has been divided in Cold-War fashion for 25 years.

A radio broadcast from the North Korean capital proposed a meeting of a "people's convention" representing the two countries this September and called for a cessation of all military hostilities.

The proposition is receiving unusual attention here and in Seoul because it was made only a few days after South Korean President Park Chung Hee proposed unification talks at any time and at any level.

The reaction was varied among analysts who specialized in Korean affairs. Japanese Foreign Ministry sources said the proposal seemed to reflect a new flexibility by the North and noted that in contrast to previous statements it contained several specific ideas for setting up the talks.

In Seoul, government officials reacted cautiously, saying only that they would study the radio broadcast for clues. Privately, they were advising reporters that it contained nothing substantially new.

The broadcast was made in the name of the North Korean Committee for Peaceful Reunification of the Fatherland, an organization active since the 1940s and suspected by South Koreans of being merely a propaganda outlet for President Kim Il Sung.

It proposed a "people's convention" to be held in either Pyongyang or Seoul this September and a return to the principles of a 1972 communique in which both sides had agred to discuss reunification.

It said the convention should be composed of representatives of political parties and social groups from both countries as well as Koreans now living overseas.

Such a meeting on nongovernmental organizations in the past has been of little interest to South Korea, which has favored direct government-to-government negotiations.

Analysts here noted, however, that on Jan. 19 President Park of South Korea had called for reunification talks "at any level." They said the North Korean broadcast appeared to be a direct response to Park's comments, which were made during a news conference in Seoul.

The major question, these analysts said, is whether the broadcast signifies a new willingness on North Korea's part to resume the long-stalled talks or is merely a routine counter-proposal timed to refute the impression that Park is more interested in negotiations than Kim Il Sung.

Japanese analysts here took the position that the broadcast was sufficiently different in tone and substance to merit serious attention.

"They are a little more flexible than before," said one Foreign Ministry official, "but we shall have to wait and see if this leads to serious business."

Negotiations on reunifying the country torn apart by the 1950-1953 war began in 1972 but were soon broken off Red Cross-sponsored talks on reuniting refugees with families have ceased.

For years North Korea has insisted it would never deal with Park's government and instead claimed it wanted to negotiate with the United States. Washington has refused to do so.

Some authorities have believed that the normalization of relations between the United States and Chinamight lead to a thaw on the Korean peninsula. North Korea has drawn closer to China in recent months, supporting that country on key issues rather than backing the Soviet Union, causing some experts to believe China is now in a position to exert pressure on the North to ease tensions on the peninsula.