Federal authorities have questioned a former chairman of the House International Relations Committee, Thomas E. (Doc) Morgan, about allegations that a former Korean ambassador visited his office on a day when the ambassador was allegedly distributing cash gifts to members of Congress.

Morgan, a Pennsylvania Democrat who retired last year after 10 terms in the House, said yesterday he had been asked about the visit by FBI agents last May and had denied seeing the ambassador on the day in question.

In telephone interviews from his Fredericktown, Pa., home, Morgan said he had had met the former ambassador, Kim Dong Jo, only on a "courtesy call" in the late 1960s and had never been offered anything by the ambassador or any other Koreans.

Kim Dong Jo, ambassador here from 1967 to 1973, is one of the several Korean agents who have been linked to a South Korean government effort to buy influence on Capital Hill.

At a hearing this fall, Nan Elder, a secretary in the office of Rep. Larry Winn (R-Kan.), told the House Committee on Standards of Official Conduct that Kim Dong Jo brought Winn an envelope full of cash in late September, 1972.

Elder testified that she returned the money after tracking down Kim Dong Jo in the office of another congressman, but she did not name that congressman at the hearing.

Morgan said yesterday the FBI was pursuing an allegation that the ambassador was found in his office that day. The former congressman said he had shown federal investigators his appointment books for the fall of 1972 to prove that Kim Dong Jo had not visited him then.

Morgan said House committee investigators had not questioned him about the allegation.