A controversial career narcotics agent, Supreme Court Justice Byron (Whizzer) White's chief law clerk, two investigators from the Senate Watergate committee and a lawyer who speaks fluent Korean are among the first staff members being hired for two internal House investigations of alleged South Korean influence buying on capitol Hill.

The House Ethics Committee tentatively approaved in closed session last week the hiring of John W. Nields Jr., 34, as chief attorney, and Andrew C. Tartaglino, 51, as chief investigator for its inquiry into possible misconduct by House members in accepting cash and gifts from agents of the South Korean government.

Nields, a graduate of Yale and the University of Pennsylvania law school, is presently senior law clerk for Justice White. For five years before that, he served as an assistant U.S. attorney for the southern district of New York, handling criminal and civil prosecutions and appeals.

Tartaglino is now with the Justice Department's liaison office to Interpol, the international office agency. He spent 23 years as a narcotics enforcement officer, with the Treasury Department, the Bureau of Narcotics and Dangerous Drugs and its successor, the Drug Enforcement Administration.

A former number two man at DEA, Tartaglino accused John R. Bartels Jr., the DEA administrator, of blocking an agency investigation of another DEA official. He made the allegations, which Bartels heatedly denied, at a Senate hearing in 1975.

A House international relations subcommittee headed by Rep. Donald Fraser (D-Minn.), meanwhile, has hired five key staff members for its study of U.S. South Korea relations.

Michael Hershman, 31, chief investigator at the Federal Election Commission, will be deputy staff director under Robert Boettcher, a former Foreign Service officer already on the staff. Hershman was an investigator for the Senate Watergate Committee and te National Wiretap Commission.

The Fraser subcommittee also has hired Fred Rayano, 41, Hershman's assistant at the FEC, Gordon Freedman, 25, a former Senate Watergate Committee investigator; Howard Anderson, 30, a deputy attorney general for the state of New Jersey, and Edward Baker, 34, a graduate of Yale law school who is now a PH.D. candidate at Harvard in East Asian languages. Baker has spent several years in Korea and speaks the language fluently, a subcommittee official said yesterday.

The House has approaved a $530,000 budget for the ethics committee inquiry and $300,000 more for the Fraser subcommittee investigation, which is expected to study broad foreign policy issues rather than allegations of individual misconduct.