The House Ethics Committee agreed yesterday on steps to receive and safeguard sensitive information from the Central Intelligence Agency for its investigation of South Korean lobbying on Capitol Hill.

In its first meeting in more than a month, the committee members signed an agreement with the CIA that would give President Carter veto power over public release of classified documents that it supplies voluntarily. Some members expressed concern about setting a precedent in conceding such power to the executive but approved the agreement in hopes of speeding the committee's investigation.

Committee investigators say they hope the secret CIA reports might name members of Congress who took money from representatives of the South Korean government.

The committee also approved a set of rigid procedures for handing such sensitive material, confining distribution to a "need to know" basis, even for committee members.

Rep. John J. Flynt Jr. (D-Ga.), the committee chairman noted that the CIA and other U.S. intelligence agencies hadn't been satisfied with earlier noted, for example that the final agreement of access to CIA material had been held up because of concern over news leaks.

Flynt also disclosed that he was negotiating for, and prepared to subpoena if necessary, an unidentified document being withheld by the Justice Department, which is conducting a paralled inquiry.

Flynt would not identify the document. But it is known that the committee has been seeking access to interviews with Kim Sang Keus, a ranking member of the Korean CIA who sought asylum in the United States last fall.

Some committee members also tossed barbs in the direction of absent committee special counsel Philip A. Lacovara for his criticism of Flynt's handling of the investigation.

Lacovara, who is vacationing in Europe, sent memos to the committee members about two weeks ago, saying that Flynt's failure to hold regular of the investigation.

Rep. Olin E. Teague (D-Tex.) said that if he had his way. Lacovara, a former Watergate assistant special prosecutor, would be fired Reps. James H. Quillen (R-Tenn.) and Rep. Walter Flowers (D-Ala.) also were critical of the chief lawyer's absence.

In a move that seemed to acknowledge some of Lacovara's criticisms, Flynt announced that the committee would meet on each of the next three Wednesdays and more often if necessary. He insisted after the meeting however, that his call for a faster pace was not a response to the dispute.

He also said that there is "a strong possibility" that the full committee could begin hearings by September.

The committee spent most of its public session discussing the implications of allowing Presiden Carter to decide any dispute between the committee and the CIA over public disclosure of classified material.

Staff attorneys insisted, though, that the committee could still subpoena any documents it feld had to be made public, if the voluntary agreement didn't work

In another development, sources said the committee decided behind closed doors to check allegations that Rep. James H. Stheuer (D.N.Y.) had paid a woman staff member for at least three months after she left the office.

The woman was identified in a syndicated column last week by Jack Cloherty and Bob Owens as being Scheuer's "alleged mistress'". Both Scheuer and the woman have denied that charge.

But the committee members were said to have agreently were the sources of the columnists' story.