The Justice Department is investigating allegations that a once highly placed CIA officer passed secrets on U.S. weaponry to the Soviets.

The former officer, David Barnett, also was said to have been paid by the KGB to try to get a job with the Senate Intelligence Committee around 1977. A committee spokesman confirmed last night that Barnett applied, but said "he was never considered" for a staff position.

One source familiar with the investigation said Barnett received about $100,000 from the Soviets.

The Justice Department refused to comment on its investigation, but the results have been presented to a grand jury and Barnett's attorney has been negotiating with Justice prosecutors. An espionage indictment or a guilty plea is expected by Friday in U.S. District Court in Alexandria.

Barnett was said to have worked as a contract employe for the CIA from 1958 to 1963 and then as a full-time staff member of the CIA's directorate of operations, which is in charge of the agency's covert actions. He reportedly left the CIA in 1970 to start his own business, but still worked part-time for the agency after that.

"It's the first time they've ever had accusations of a CIA covert agent passing secret to the Russians," one source said, adding that the officer in question far outranked William Kampiles, a former CIA clerk convicted several years ago of selling a top-secret CIA satellite munual to the Soviets. However, another source noted that Kampiles gave much more damaging information to the Soviets than Barnett is suspected of selling.

Barnett, who could not be reached for comment, was said to be under investigation for handing secrets to the Soviets in his capacity as a part-time worker for the CIA and as an old hand who kept abreast of various developments through his contacts at the agency.

"It's a very serious allegation," one source said. "Kampiles had a low-level job. This guy had a high-level covert position."

The reported effort to gain a staff job with the Senate committee never got very far, sources said. Barnett was also said to have tried to get a position on the House Intelligence Committee and on the administration's Intelligence Oversight Board in recent years, but was unsuccessful with those applications as well, sources said.

Like the Kampiles case, the investigation of Barnett raises questions about the adequacy of CIA internal security procedures.