The House Committee on Standards of Official Conduct ended the first phase of its hearings on the Korean inffluence-buying scandal yesterday with the assertion that testimony had proven beyond doubt that the government of Soutn Korea director illegal efforts to influence members of Congress and other U.S. officials.

"There was an oficial plan, and it was executed," said Peter White, the committee's deputy special counsel in a summation of the testimony of 14 witnesses during the three days of hearings.

"The question of whether these things took place is, very simply, a dead issue," White said as the committee chairman, John J. Flynt (D-Ga.), nodded in agreement.

As a result, White suggested that the committee propose a House resolution condemning South Korea for its failure to cooperate with American investigations of the influence-buying scheme. Several members of the committee said later that they would support such a resolution.

Congressional Justice Department investigations, have been frustated in efforts to gather evidence from several South Koreans, including Tongsun Park, the businessman and socialite who was allegedly a central agent in Korean efforts to buy friends and influence in Washington.

In Seoul yesterday, negotiations over American interrogation of Park ended in failure as a Justice Department team reported that the Korean had failed to offer acceptable conditions for the questioning.

The Korean embassy here has regularly said thar Park and other individuals involved in the influence-buying program were private citizens whose actions had no connection to the Seoul government or its officials.

At yesterday's hearing eight witnesses including a former director of the Korean Central Intelligence Agency - reiterated what had come before: that Park acted as an agent of the Korean government, reporting regularly to government officials and indirectly receiving funds from the government to support his efforts in Washington.

Testerday's testimony also showed that Park used contacts with members of Congress and their aides to further his work on Capitol Hill.

Kim Hyung Wook, who was director of the KCIA from 1963 to 1969, told the committee that former Rep. Richard T. Hanna (D-Calif.) proposed a rice brokerage position for Park that provided funds he used to win favor with members of Congress.

The testimony showed that Park was able to place a young Korean associate briefly in the offices of two different members of Congress to gain "training on the Hill."

The former Park associate, Jay Shin Ryu, who testified under a grant of immunity from criminal prosecution, said that when he arrived in the United States in 1970 Park set up a meeting with Robert Reveles, a staff aide to Rep. Frank Thompson Jr. (D-N.J.), during which Reveles offered Ryu a job as an intern in Thompson's office.

Ryu said he was on the job within a week after his arrival in the United States. He said he was paid $400 monthly in the job. The payments were made in cash and came, as Ryu later learned, from Tondsun Park.

After 3 1/2 months in Thompson's office Ryu said tongsun Park urged him to go to the Senate side." Park then arranged a similar internship for Ryu in the office of then Sen. Joseph M. Montoya (D-N.M.).

Ryu worked for Montoya for 3 1/2 months, he said, and was paid during that period as well by Tongsun Park.

Officials in congressional payroll said yesterday that congressional internes are sometimes paid by outside groups such as universities.

Montoya was unavailable for comment yesterday.

Bill Dietz, Thompson's chief aide, said Thompson's staff considered Ryu volunteer intern. "We've had dozens of these volunteers over the years," Dietz said. "The guy was down in the basement on the Education and Labor Subcommittee.

Montoya could not be reached. His wife said in a telephone interview that Ryu's story sounded "ridiculous."

Former Rep. Hanna, in contrast, was depicted in the testimony as an active advocate for Tongsun Park's interests.

Kim Hyung Wook, the former KCIA director who has since defected to the United States, told of a meeting at KCIA headquarters in August, 1968, in which Hanna and Tongsun Park urged that Park be named exclusive agent for Korean rice purchases in the United States.

The witness said that Hanna and Park urged this appointment so that Park could earn brokerage fees on the rice purchases and "distribute that money among U.S. congressmen and have them aid Korea's cause."

Hanna was indicted last week on federal charges of bribery and failing to register as a foreign agent for his role in the Korean scheme. According to the indictment, the meeting Kim Hyung Wook described took place in 1967, not 1968 as yesterday's testimony indicated.

The committee next heard testimony from rice sellers in the United States who indicated that the Korean government had in fact designated Park exclusive agent for U.S. purchases.

Cheryl Holmes, a financial anaylst on the committee staff, said her review of Park's finances showed he received $9.2 million in rice commissions during 1968 to 1976.

Holmes, who said she reviewed Park's accounts in 10 banks and his commission payments from two American rice sellers, said that figure represented lmost all of Park's income during that period. But Holmes said Park also ahd accounts in foreign banks where she could trace the records.Kim Hyung Wook and another former Korean official Lee Keun Pal, told the committee that Tongsun Park regularly reported his activities in Washington to KCIA officials in Seoul and at the Korean embassy here during the period 1966 to 1976.

Lee, who worked in the embassy here, also noted that in 1969 or 1970 the U.S. State Department complained to the Korean embassy about its lobbying activities in Congress. He said the State Department insisted that it be informed of future Korean contact with members of Congress.

After that complaint, however, Lee said, the embassy stepped up its lobbying activity under pressue from the Seoul government.

As in the previous two days' hearings, yesterday's testimonydrew little emotion at the committee table or in the audience.