Anti-industry congressional testimony by two former Federal Power Commission officials "contributed significantly" to attempts to fire or transfer them, a House investigation concluded yesterday.

Congressional investigators said that these and other personnel shuffles hindered FPC regulation of the oil industry during severe natural gas shortages in 1975.

While no clear violations of federal law were found, the House Commerce Subcommittee on Oversight and Investigations said "an unusual series of 'coincidences' were encountered."

Two FPC attorneys, George Lewes and Russell Mamone, testified at January, 1976, House hearings that Tenneco Oil Co. and Mobil Oil Corp. had withheld natural gas supplies from federally regulated interstate pipelines. The natural gas was diverted to unregulated intrastate pipelines where gas commands higher prices.

FPC officials told House investigators that retaliatory action, along with efforts to fire Lewes, were taken after his testimony. Lewes was then an FPC assistant general counsel with 16 years of government service.

According to House investigators, the order to fire Lewes orginated with former FPC Chairman Richard L. Dunham. Months afterwards, Lewes voluntarily accepted an appointment as an administrative law judge.

Mamone, an FPC attorney specializing in natural gas regulatory questions, was transferred to a section handling hydroelectric licensing maters, an area in which he had no experience.

Anothe FPC official, Jon Lotis, was hurriedly transferred from his position as head of the Gas Pipeline and Electric Rate Section after an embarrassing set of memos to and from Lotis were included in the House Investigations Subcommittee's record. "Mr. Lotis has never inexpliicably reorganized out of his supervisory responsibilities and give a position handling one or two cases with no comparable responsibility," the House report said.

The House investigatio, which is directed by Rep. John E. Moss (D. Calif.), sought to determine whether FPC officials, including then-Chairman Dunham, had violated federal law by intimidating FPC staff members for giving potentially embarrassing congressional testimony.

Earlier this year Dunham and another FPC commissioner, James Watt, denied that there had been any effort to punish Lewes, Mamone or theirs for their testimony. The transfers were intended to improve FPC management, Dunham said.

The Moss panel said no final conclusion could be reached on whether federal law had been broken, adding that Lewes' and Mamone's testimony "contributed significantly to adverse personnel actions that were taken or attempted against them."

The FPC was folded into the newly created Energy Department Oct.1. A department spokesman said the matter is closed.