Korean opposition leader Kim Young Sam said yesterday that the Olympic Games scheduled for Seoul in 1988 could be "in jeopardy" because of internal political unrest unless a "climate of increasing repression" in that country is eased.

Known along with former Washington area resident Kim Dae Jung as one of the "two Kims" at the forefront of political opposition in South Korea, Kim Young Sam was interviewed as he began his first visit here in nearly seven years.

Kim said the political opposition, which now controls more than one-third of the South Korean parliament, does not object to Seoul's selection as site of the 1988 Summer Olympics, which are expected to draw intense international attention to the South Korean capital.

He said, however, that "there can be no stability" as long as the government of President Chun Doo Hwan "ignores the opposition, students, labor" and others calling for internal change. This lack of stability "would endanger the Olympics," Kim added.

Kim said that North Korea should be invited to enter a separate team in the Seoul Olympics but that joint or concurrent sponsorship of the Games with North Korea would be "difficult."

His central demand, Kim made clear, is for revision of the Korean constitution to replace an indirect presidential election system with popular elections when Chun's seven-year term ends in 1988.

The election is scheduled for March 1988, about six months before the Olympics. Kim said his greatest fear is of another military coup, such as those that brought Park Chung Hee to power in 1961 and Chun to power in 1980, which could "delay the process of democracy."

Kim said there is "no chance for Chun to run again" in view of the president's repeated statements that he will not. Moreover, "I don't think any hand-picked [Chun] person could be elected," Kim said.

He and Kim Dae Jung, often rivals, "are determined to unite not only for 1988 but afterwards," Kim Young Sam said.

The Kims are considered the nation's most important opposition leaders, although neither holds a formal position in the New Korea Democratic Party, the major opposition party. No decision has been made about which one, if either, will be the opposition's major candidate in 1988.

Kim said the most important question for South Korean politics involves relations with North Korea. He said "no fundamental difference" exists between government and opposition regarding relations with the communist North.

He added, though, that "democratic rule" under a popular government in the South would provide the best opportunity for dialogue with the North. In his view, he made clear, this means an opposition-party victory in Seoul.