Not far from the ocean, hard by Richard M. Nixon's Casa Pacifica at San Clemente, stands a $20 million monument to the doggedness of bureaucracy.

It is a building nobody wanted to buy, nobody wants to use, nobody seems to need, nobody can justify.

Yet the General Services Administration, the federal government's real estate agent, is asking Congress to approve $3.3 million to alter and repair the building in hope of landing a tenant.

The structure at Laguna Niguel, in a remote corner of affluent Orange County south of Los Angeles and 10 miles from San Clemente, has been described variously as:

"A white elephant searching for a purpose" - Rep. Glenn M. Anderson (D-Calif.).

"A lemon the federal government picked up" - Rep. Robert W. Edgar (D-Pa.).

"Studyidity of the General Service Administration" - Rep. Jack Brooks. (D-Tex.).

"A valuable asset . . . although I probably never would have touched (bought) it" - Robert T. Griffin, deputy assistant, GSA administrator.

Laguna Nigueli, in the view of congressional critics, is only a more flagrant example of GSA property-management practices that are widespread and cavalier. The agency, overseer of a multibillion-dollar real estate empire is accused of illegally bypassing Congress and disregarding policy on building site selection.

GSA's acquisition of the enormous structure - it is about one-fourth the size of the Pentagon - has been investigated and critized by two congressional committees. The General Accounting Office raised serious questions about it in several probes.

Through it all, there remains one constant GSA is struck with the building, and is try feverishly to find some use for it.

When GSA obtained the building in a property trade with a major defense contractor in 1974, it denied that it intended to use the place for storing records from Nixon's public career.

It turns out, however, that a small section of the mostly vacant building 10 miles form the former President's residence, is being used to store record, oral history taps and memorabilia form Nixon's presidential career.

Since GSA acquired the seven-storey structure in the trade with Rockwell International Corp., it has tried assiduously - mostly to no avail - to attract federal agencies in Southern California to relocate at Laguna Niguel.

GSA's efforts included polling more than 40 different agencies, holding tours for prospective federal tenants and circulating a handsome brochure that promotes the lure of living and working in a sun-kissed wonderland.

Prospective tenants with multitudes of low- and middle-income employees say new homes average more than $120,000 in Orange County, public transportation is limited, freeways are crowded and the cost of living high.

But GSA has a possible tenant on the line, a regional office of the Defense Contract Administration Service, which now rents quarters for its 800 employees about 50 miles away next door to Los Angeles International Airport.

The proposal has set off one more in the long string of Laguna Niguel controversies.

Many of the defense auditing outfits employees - half of whom earn less than $10,000 per year - would have to relocate, commute to Laguna Niguel or give up their jobs.

Orange County has neither the low-no medium-income housing available for an influx on that size, although local officials have begun to develop affirmative action plans and the Department of Housing and Urban Development has promised to assist in building some units.

Democratic Rep. Charles H. Wilson, whose 31st District covers most of the ployees, described the proposed move of the agency as an attempt by GSA to justify its acquisition of the unwanted building - at the expenses of his constituents.

"You must make the GSA face the facts . . . GSA simply cannot justify the retention of this building," Wilson told the House Public Works Subcommittee on Public Buildings and Grounds. "Let GSA admit its mistake, not perpetuate it."

Rep. Brooks, chairman of the Government Operations Committee, which investigated the property trade and issued a scathing report last year, said the proposed $3.3 million for renovation would be "only the beginning" of the government's expenses. Transfering workers and housing them in Orange County would require federal rent supplements of about $1 million a year, Brooks' committee learned.

"They have a bear by the tail and they are trying to get rid of it . . . A principle of good management is that you do not send good money after bad," Brooks said.

"You take your losses . . . To force occupancy of Laguna Niguel as a federal office building simply because it is there would be to compound a mistake, not to correct it."

Brooks also urged a broader investigation of GSA property-trading practices.

The California deal, he said, was "a classic case study in how a government agency can manipulate procedures to bypass Congress and circumvent the law."

The Public Building Act of 1959 held that GSA could not trade any federally owned properties valued at more than $500,000 without the consent of Congress.

Rep. Norman Y. Mineta (D-Calif.), chairman of the public works subcommittee, said that since 1975 GSA apparently has violated the law at least six times in swapping properties from the U. S. Postal Service.

Explaining its acquisition of the Laguna Niguel building without congressional approval, GSA said it felt the law did not supply since the only expense involved was some $32,000 in property transfer costs - well below the $500,000 limit.

This week Mineta's subcommittee will visit Laguna Niguel and hold hearings in the area to learn more about GSA's request of $3.3 million for repairs and alteations.

"There is no question about what happened at Laguna Niguel," Mineta said." It was a bad deal and we never should have been sucked into it. I'm convinced we didn't get dollar-for-dollar on the deal. But our problem now is whether we try to fill the building or declare it surplus."

Beyond the issue of Laguna Niguel, he added, the subcommittee intends a fuller exploration of GSA's trading of surplus federal properties without congressional approval.

"They are backdooring so many exchanges that I'm very bothered about it. They say their policy now is that they will notify us when they intend to make an exchange, but they don't expect us to veto.The law is cut and dried on this. I want these matters brought to us." Mineta said.

GSA Griffin told the subcommittee that if Laguna Niguel's acquisition had been proposed to the current administration at GSA "it would not have been completed."

But, he insisted, Laguna Niguel remains a valuable property that could, with congressional cooperation, be fully utilized within five years by federal agencies and result in huge savings on rentals now being paid for office space - more than $210 million over the next 30 years.

The seven-story building at Laguna Niguel, surrounded by 58 acres of parking space, now provides haven mostly for the GSA as a records center and for small units of the departments of Defense, Treasury, Interior and Agriculture.

With 300 employees, they occupy about one-tenth of the building, GSA spends $600,000 annually for operation and maintenance - which includes weekly flushing of toilets and running of escalators just to keep them functional.

Details of the Laguna Niguel deal surfaced three years ago in a Washington Post investigation. Although the Office of Management and Budget objected, aides at the Nixon White House pushed the transfer in 1971 because the site seemed perfect as storage for the Nixon records and as projected office space for the Western White House.

GSA denied that the building was sought for that purpose, but this was refuted by documents at its San Francisco regional office. The files indicated that final approval for the deal came after Robert H. Finch, a presidential assistant, interceded. Finch asknowledge doing so.

Subsequent congressional and GAO inquires have indicated that GSA get stuck with a building for which it had little use since - especially the Nixon presidential papers are being kept at the National Archives here in Washington by an act of Congress. CAPTION: Picture, $20 million structure acquired by GSA in 1974 sits, mostly vacant, on 91-acre site in Laguna Niguel. AP