Tongsun Park, the South Korean businessman who is a central figure in investigations of influence buying in Congress, broke a long silence yesterday to defy U.S. authorities who are trying to get him to return from Seoul for questioning.

Leon Jaworski, new special counsel to a House committee investigating the allegations, said he was not surprised by Park's remarks and was still confident the key witness could be brought before the committee.

In any event, Jaworski told reporters after his first meeting with members of the Committee on Standards of Official Conduct, "I don't think his testimony will make cases or be fatal to cases."

In a prepared statement he read during a brief public portion of the meeting, the former Watergate special prosecutor made several allusions to the executive branch scandal that toppled President Nixon.

Jaworski said there were indications that, as in Watergate, some people were trying to cover up the truth of charges that the South Korean government, through Tonsun Park and others, had showered members of Congress with cash, gifts and entertainment.

The committee, like the Justice Department which is conducting a separate but parallel criminal investigation, has had difficulty getting testimony from key figures such as Park.

In fact, the committee discussed but did not vote yesterday in closed session on whether to cite another potential witness, former congressional aide Suzi Park Thomson, for contempt becuase she has refused to cooperate.

Jaworski also called on the South Korean government "to extend unlimited cooperation to this committee and its investigators." This was an apparent reference to so-far-unanawered appeals to the Seoul government for aid in returning Park, who flew unexpectedly to Korea from London last week to visit his seriously ill mother.

The South Korean government has consistently denied any connection to Tongsun Park, a claim Park himself echoed in apress conference in scoul lyesterday.

South korean prosecutors questioned Park for more than an hour before that press briefing, reportedly in an effort to determine if he had broken any Korean laws while conducting his wide-ranging international business dealings.

The Washington Post reported last month that Park's personal financeal ledger for 1970 showed he regularly changed Korean won for dollars for other South Koreans, in apparent effort to help friends evade government currency restrictions.

In addition, a former director of the Korean Central Intelligence Agency told a house subcommitte in June that he helped Park change $100,000 worth of won into American money in the mid-1960s and shipped the cash to him by the embassy diplomatic pouch.

That same witness said he furnished Park with $3 million in Korean government funds to be used as collateral for loans needed to operate the George Town Club, the exclusive Washington supper club where Park entertained American politicians.

In his remarks in Seoul yesterday, Park said the former KCIA director, Kim Hyung Wook, "must have been affected by the heat when he said that. I have nothing to do with the money he talked about."

"Ialways enjoy the company of political figures and that happens to be my hobby," he said. He said it was "absurb" to say he was part of a Korean government strategy to influence Congress.

"Whatever I have done . . . has been done for my personal account as a private businessman," he said. Congressional friends from rice-producing states did come to him in 1967, he added, to ask his help in selling surplus rice to Korea.

Most of the money he earned as a middleman in these deals - $8 million from one American exporter during a four-year period, according to Internal Revenue Service figures - was used to "establish schools, which has been my mother's life-time dream," Park said.

The IRS figures, however, show that huge sums of money were transferred from his accounts in Korea to banks in Bermuda during the early 1970s. From there, the money was often wire transferred to an account in Baltimore, where armored cars routinely picked up large cash bundled for delvery to his Washington homes, former Park associates have told The Post.

Some members of Congress have acknowledged receiving large cash sums from Park. Others are recorded in the same ledger book in which he detailed his fees from the rice deals.

Justice Department and congressional investigators are known to believe that Park often exaggerated his claims fo payments to members to impress South Korean officials. But they still are anxious to question him about alleged payments only he could corroborate.

In a related development, the name of Washington lawyer John H. Pickering surfaced as a possible special counsel to the Senate ethics committee, which is now gearing up for its own study of Korean lobbying.

An aide to Sen. Adai Stevenson (D-Ill.), chairman of the committee, confirmed yesterday that Stevenson had talked to Pickering, a senior partner in Wilmer, Cutler and Pickering, one of the city's most influential law firms.

Pickering, who is 61, declined to comment yesterday.