A long-awaited House report released this week blasts the Commodity Futures Trading Commission for scores of questionable practices, including some involving a $950,000 contract to furnish its headquarters, a $159,000 advance payment on its building lease, and "flagrant" misuse of authority to hire consultants.

Investigators for the House Appropriations Committee studied the agency's operations and records for more than six months in order to complete the 137-page study.

Among the report's findings is that the agency repeatedly circumvented General Services Administration procedures and regulations in awarding contracts and in signing leases and other agreements.

In furnishing its headquarters in 1975, the CFTC accepted seven bids, but then cancelled its procurement action and awarded a $950,000 contract for furniture "superior" to government standards to a firm that submitted a late bid.

The award represented a "disregard for GSA regulations, unusual contract terms and questionable sole-source designation, unjustified use of a cost-type contract and an imprudent advance payment to the contractor," the report says.

The former general counsel of the CFTC refused to ratify the procedures used, "contending that as a matter of conscience he would not be a party to what he believed to be a violation of the law," the study continues.

The agency also awarded two purchase orders totalling more than $17,-000 noncompetitively on the same day to a former employer of a CFTC official. "The purchase orders were split purposely to remain below $10,-000 each to avoid certain statutory requirements," according to the study.

The CFTC Repeatedly used its authority to hire consultants and outside experts as a means of "accelerating the hiring of top-level personnel" -- A "flagrant miuse of the authority." The cases "are particularly indefensible in view of the position of CFTC that it is understaffed and underfunded."

The report said the commission hired 41 consultants for its advisory committees, and 10 of the 41 subsequently became permanent agency officials, including the acting executive director, general counsel, chief economist and division directors.

The study quotes the Civil Service Commission as saying that the CFTC's attempts to place a large number of jobs in the exempted Scheduled C category, when many of the jobs did not meet Schedule C criteria, "went beyond the bounds of reason" considering the size of the agency. The total staff of the CFTC is about 450.

The report alleges poor planning, lack of administrative organization, and poor internal financial controls.

Contributing to the early organization problems were the rivalries between and among the new senior-level appointees," the study said. "None of the senior staff involved is still employed by the CFTC."

"The major points of contention, in addition to personality conflicts, were 'turf battles,' with each of the individuals jealously guarding his or her own sphere of authority and trying to expand his or her own jurisdiction and influence. The bickering among the upper-echelon personnel had an adverse effect on the subordinate staff, and there was no clear delineation of authority or responsibility," it continues.

The report notes that, while the early problems largely have been resolved, they have not disappeared.

CFTC Chairman William T. Bagley's comments on the report were in defense of the furnishing arrangements made by the agency. He said "we got a very good deal" on the contracts.

Vice Chairman John V. Rainbolt II commented yesterday on the report by saying, "It's never been any secret we've got administrative problems. Many are linked to the office and function of the chairman.