In an effort to avoid recurrences of the South Korean influence-buying scandal, a Senate subcommittee is preparing legislation that would require U.S. intelligence agencies to warn Congress when members are approached by clandestine agents of foreign governments.

The legislation, part of a broad effort to write regulations governing the security agencies, reflects the suspicion of some members that the Central Intelligence Agency knew about the SouthKorean scheme in the early 1970s but failed to warn Congress.

Two congressional committees are investigating whether the CIA had evidence of ties between the South Korean government and businessman Tongsun Park, who gave gifts, made contributions, and provided entertainment for many members of Congress.

Park and Hancho Kim, another Washington-based businessman, have been indicted on federal charges that they were involved in a secret effort by the Korean government to win support in Congress through bribery.

The House Subcommittee on International Organizations plans to open hearings late this month probing how much U.S. security agencies knew about the Korean effort, and whether they withheld what they knew from Congress.

The Senate Intelligence Committee's staff has been investigating the same questions, and will recommend to the committee soon whether separate Senate hearings should be held.

Meanwhile, the Senate committee's Charters and Guildelines Subcommittee has been working on statutory language that would require the intelligence agencies to keep Congress informed of attempted contacts by clandestine foreign agents.

The subcommittee is preparing a set of "mandates to govern the operations of the CIA and other intelligence agencies.

"One thing that will be in our draft statutes," says Elliott Maxwell, of the subcommittee staff, "is reporting requirements to Congress.

"We want to make sure that . . . if there are activities by governments that involve violations of law that the agencies know about, that they will be communicated to Congress."

Details of the reporting law have not been resolved. Presumably, Congress would designate each house's Intelligence Committee as the recipient of the reports.

Such a statute would make permanent an oral agreement between the CIA and the Intelligence Committee under which the agency has been reporting to the committee about undercover foreign agents who have tried to make contact with senators.

"Nowadays, they're telling us about the activities of representatives of foreign countries," said Sen. Adlai E. Stevenson (D-Ill.) a member of the Intelligence Committee. "It would be better to have an explicit mandate in law so we could always be sure that we'd be informed."

The Intelligence Committee chairman, Daniel K. Inouye (D-Hawaii), has declined to comment on the agreement with the CIA.

Last winter Inouye was the center of an imbroglio over reports that he had asked the CIA to be on the lookout for foreign agents who might "target" Intelligence Committee members.

Some senators expressed concern then that Inouye's request might lead to regular surveillance of members of Congress. Inouye assured his colleagues that would not happen.

The proposed legislation imposing a "reporting requirement" on the CIA raises similar concerns.

"We're going to have to be careful in this area," said Sen. Charles McC. Mathias Jr. (R-Md.). "If they're going to tell us when foreign agents have had dealings with senators, then they have to keep track of the senators.

"You raise a lot of problems with gathering and passing all this information around," Mathias said.

The charters subcommittee - or which both Stevenson and Mathias are members - is expected to consider the proposed "mandates" before Congress adjourns this year.

The question of reporting requirements will be influenced by whatever turns up in the investigations of the CIA's knowledge of the Korean influence-buying effort.

Stevenson is one of several members of Congress who suspect that the agency failed to pass Congress it information about individuals who operated here as secret representatives of the South Korean government.

"To give the agency its due, you have to consider why they might not have reported to us any information they had obtained," Stevenson says.

"One simple reason might have been that there was no forum, no Intelligence Committee, for the agency to report to then [in the early 1970s]. On the other hand, when you consider the other things that happened in the Nixon Administration . . . who can say?"

In an interview with The Washington Post in August, Stansfield Turner, the director of central intelligence, would neither confirm nor deny that the CIA knew of ties between Tongsun Park and the Korean CIA.

But Turner said "all relevant information the CIA had on Park or KCIA activities was passed to the appropriate officials in the executive branch."

In addition to his seat on the INtelligence Committee, Stevenson chairs the Senate Ethics Committee, which is in the process of hiring staff investigators to probe possible Senate involvement in the South Korean influence-buying effort.

A Washington Post survey of present and former senators suggests that Korean lobbying activities in the Senate were not as intense as that nation's effort in the House.

Of 82 present and five former senators who answered a Post question-naire, no more than handful said they had had more than passing contact with South Korean institutions or government officials, or with Tongsun Park or other individuals believed to have been part of the influence-buying effort.

In responses to an earlier Post survey, many House members recalled offers of gifts or free travel or campaign contributions from Korean sources.

Six senators said they had been offered free trips to Korea; in five of those cases the offer included an honorary degree as well from a Korean university. All six said they declined the offers.

One senator, Jake Garn (R-Utah), said he traveled to Korea last year at the expense of the Korean-U.S. Economic Council, and other Republican senators said staff aides had received trips to Korea from the council.

According to the State Department, the council describes itself as a non-profit organization funded by private firms.

Several senators who answered the Post survey offered the opinion that influence-buying efforts by foreign nations are "not widespread" in the Senate.