Secretary of State George P. Shultz praised the South Korean government today for "moving pretty fast" toward a stable democracy despite violent student demonstrations and 25 years of authoritarian rule.

"I'm impressed," said Shultz in remarks that placed the U.S. administration squarely behind President Chun Doo Hwan's government and gave short shrift to opposition party demands for direct presidential elections and an end to press control and secret police repression.

Shultz's remarks came as he flew from the Tokyo summit to begin a 24-hour stay here amid highly charged political controversy. The government and its moderate opposition are disputing the constitutional ground rules for selection of a successor to Chun, a former general who took over through military means but has promised to relinquish power in early 1988, in what would be the first peaceful transition since Korean independence at the end of World War II.

Several thousand students and workers, many shouting anti-American slogans, clashed violently with police Saturday at nearby Inchon in what the Korean press has described as the most serious domestic disorder in six years. The demonstrators also shouted slogans against the main opposition party and burned a car emblazoned with opposition colors.

Shultz, condemning "violent confrontations" and "an opposition which seeks to incite violence," seemed to take the side of the ruling party in putting some of the blame for the clashes on the opposition party.

Lee Min Woo, the lesser known president of the opposition New Korea Democratic Party is among 12 Koreans invited to breakfast with Shultz Thursday, but Shultz has no plan to meet Kim Dae Jung and Kim Young Sam, the two most important and best known opposition figures.

The two Kims had been scheduled to meet Assistant Secretary of State Gaston Sigur, but they revoked their acceptance early today under disputed circumstances. Kim Dae Jung said the U.S. Embassy had added two other Koreans to their planned meeting with Sigur "without notice" making the session unacceptable. U.S. Embassy officials said the guest list had included the two disputed individuals all along. Korean sources indicated that Kim Young Sam objected to meeting Sigur on protocol and prestige grounds. Most of Shultz's time will be taken up in meeting Chun and his senior government officials.

U.S. officials said in advance that Shultz will push compromise and dialogue, rather than confrontation, as a solution to this country's increasingly tense political discord. Shultz's unusually extensive discussion of the Korean political scene with reporters aboard his airplane en route from the summit in Tokyo seemed unlikely to contribute to reconciliation.

"There is a terrific job being done in the economy and a progressive movement going on in terms of the institutions of democracy and the prospect of an orderly change of government," said Shultz in assessing the South Korean situation.

Positive political change is "moving pretty fast" and maintaining "a pretty good pace in the system," Shultz added.

Asked about house arrests of opposition figures, Shultz replied that, "I didn't say the situation is perfect. I said it is moving impressively very much in the right direction."

When a reporter asked about Shultz's view of press censorship in Korea, Shultz expressed support of the Chun government and said, "We have a lot of admiration for the way the Korean institutions have evolved and managed things in the last few years."

In a meeting with Foreign Minister Lee Won Kyung shortly after his arrival late this afternoon, Shultz discussed the 30,000 South Koreans working in Libya, but did not ask that they be withdrawn, according to a U.S. briefing.