While public attention in the South Korean influence-buying investigation continues to be focused on the Justice Department's efforts to get testimony from accused South Korean agent Tongsun Park, the House committee conducting a parallel inquiry is much more interested in talking to former Korean ambassador Kim Dong Jo.

Investigators for the House Committee on Standards of Official Conduct consider the most significant testimony in their recent hearings on the Korean government-sponsored lobbying campaign to be the identification of Kim as the official who gave an envelope stuffed with $100 bills to Rep. Larry Winn Jr. (R-Kan.) in 1972. Winn returned the money.

The testimony was considered important because it corroborated statements by another witness, former embassy official Lee Jai Hyon, who said he was Kim carrying at least two dozen envelopes filled with cash to the Capitol in the spring of 1973.

"Tongsun Park can't tell us who Ambassador Kim delivered those envelopes to," jeffrey Harris, the House investigations deputy chief counsel said yesterday.

Both Harris and John W! Nields Jr., the chief counsel, emphasized that they wanted to talk to Park, too.

The Justice Department has concentrated on trying to get Park's testimony because diplomatic immunity protects embassy officials such as Kim.

Leon Jaworski, special counsel to the House committee, said in remarks at the recent hearings that he rejected an invitation to go to Seoul to talk to Park because the Korean government wanted to limit the talk to Park and not to other government officials such as Kim.

The committee is known to have asked several months ago that the Korean government waive diplomatic immunity in the case.

Meanwhile Justice Department officials yesterday discounted press reports from Seoul that said agreements had been reached on a plan to allow their investigators to question to Park in the American embassy on whether he might return to the United States to face federal conspiracy and bribery charges.

The Justice officials reiterated earlier statements that any agreement to question park would have to include safeguards to ensure the truthfulness of his testimony and its admisibility in a trial in a U.S. court.

This would mean some arrangement for a lie detector test and some means of cross-examination by defense attorneys, perhaps by videotape, if Park did not actually return to the United States.

In a related matter, House Speaker Thomas P. O'Neill Jr. (D-Mass.) released a letter from the committee yesterday which said it had no evidence his rent had been paid "by anyone else."

A few weeks ago, the committee subpoenaed O'Neill's rent records after getting a tip that Tongsun park had paid some of the bills. "This was a crackpot rumor to start with and we hope this puts an end to unfounded allegations in the future," O'Neill said in a statement.