Accused South Korean agent Tongsun Park will return to Washington "In a matter of days" to tell House and Senate investigators about payments he made to members of Congress.

But House Speaker Thomas P. (Tip) O'Neill Jr. said in announcing the breakthrough yesterday, that the Korean government is only temporarily safe from a threatened cutoff U.S. aid.

O'Neill warned Korean Ambassador Kim Yong Shik 10 days ago that continued aid to Korea was in jeopardy because of the Seoul government's refusal to make Park and other witnesses available to congressional investigators.

Kim met privately with House and Senate leaders yesterday and reported that his government had no objection to having Park testify in closed sessions with congressional investigators, O'Neill said.

But the Korean still refuse to make former diplomats, such as onetime Ambassador Kim Dong Jo, available to testify here.O'Neill said .

Thus, while O'Neill called Park's return "an important first step," he reserved judgment on the status of continued U.S. aid to Korea.

He said "we left the door open for further dialogue" on information former Ambassodor Kim might have on alleged cash payments to members of Congress.

"We have to take it one step at a time," O'Neill said when asked if the Korean response was adequate to head off moves to cut off aid.

He said he didn't think a House resolution demanding full cooperation would be scheduled for a vote now. But he added that further action could be taken when the first budget resolution comes up March 15.

"We'll see what happens to the testimony of Tongsun Park," O'Neill said "We'll see what happens when the committee decides it needs more information from the Korean government."

The Senate Ethics Committee will also question Park, its leaders said yesterday after also meeting with Kim Yong Shik.

O'Neill's personal warning to the Koreans about future U.S. and trigered a response that the Seoul regime of President Park Chung Hee was unwilling to make under more subtle pressures from the executive branch.

The Justice Department, after months of negotiations, signed an agreement for restricted questioning of Park in Seoul and His testimony in criminal trials in the United States.

In return, the deparetment agreed to drop a 36-count felony indictment against him and try to persuade the congressional committees to forgo questioning Park. But Justice officials made it clear they could not speak for the Congress.

Assistant Attorney General Benjamin R. Civiletti, who led the Justice Department team questioning of Park said last night that he was pleased to hear that Congress also would be allowed to question Park.

But he repeated concerns about the timing of expected public testimony from Park before the Committees.

Civiletti has said before that he hoped Congress would postpone such public hearings until after Park's appearance as a witness in Criminal trials.

Park is expected to be a government witness at the March 20 trial of former Rep. Richard T. Hanna, the only current or former member of Congress indicated so far in connection with the Korean lobbying campaign.

Park is reported to have told Justice Department prosecutors in Seoul that he made about $1 million in payments to several members of Congress over a multi-year period ended in 1975. He left Washington in the fall of 1976 and has been in Seoul since shortly before his indictment last August.

Park generated the money for his gifts to members of Congress in large part from commissions he received as the Korean government's exclusive agent for buying rice in the United Stated.

The Korean government consistently has denied any connection with the rice broker and insisted that the Justice Department not question Park about his denies with current Koan government officials.

O'Neill said yesterday that the House would have "no restriction" in its questioning of Park. House investigators need to make the Park-governments connection to show that members who accepted his gifts and campaign contributions were dealing with a foreign agent.

Civiletti said when he returned fro Seoul that he expected only a handful of additional criminal indictments.