Students protesting the authoritarian rule of President Park Chung Hee battled police with rocks today in the most violent antigovernment demonstration here in more than two years.

Riot police and plainclothes policemen eventually routed the estimated 4,000 students from the grounds of Yonsei University, the country's largest Christian school of higher learning.

There were no reports of injuries. Witnesses said that between 40 and 50 students were taken into custody.

The incident began with a noon rally on the campus attended by 800 persons. Yonsei was closed 17 days ago because of another student protest and had just resumed classes today.

The students adopted a resolution calling for withdrawal of the country's five-year-old constitution, restoration of campus freedom and resignation of the "dictatorial regime." They also adopted a resolution calling on the government to "clarify the Tongsun Park case," in which South Korean government agents have been accused of bribing members of the U.S. Congress. An accompanying declaration charged that the government had resorted to diplomacy-by-bribe. It said the case was the "biggest national disgrace" since Korean independence in 1948.

Following the rally, the students, then numbering 4,000, gathered near the school's main gate. They chanted, "Out with Park Chung Hee," and "Withdraw Revitalization," the government's term for President Park's authoritarian system and his prohibition against public dissent.

About 200 riot police and scores of plainclothesmen, led by vehicles spraying a pungent "pepper fog" gas, stormed into the campus. The students drove them back with rocks.

Finally police reinforcements arrived and another charge was mounted. The students scattered, some of them being seized by police.

In a related development, a National Assembly member from the opposition New Democratic Party, Hahn Yung Soo, called today for the resignation of Kim Dong Jo, a special assistant to President Park, because he was the ambassador in Washington when most of the alleged South Korean payoffs were made. Testimony in the U.S. grand jury investigation also said that Kim had personally delivered some of the payoff money.

Hahn made his demand in the assembly's foreign affairs committee. Foreign Minister Park Tong Jin told the committee he was not in a position to speak for Kim on such a personal matter.