Through the portals of the European Economic Commission headquarters pass 10,000 of the world's most-favored civil servants.

As the result of a vast web of tax-protected salaries and fringe benefits,the "Eurocrats" who handle the day-to-day tasks of the Common Market reap incomes that would bring tears to the eyes of an American GS-13.

Many of the Eurocrats, moreover, are not exactly overworked.

When they were hired, the Eurocrats were expected to initiate policies in fields like trade, energy, industry, and agriculture that would serve as the foundation for what visionaries hoped would become a "United States of Europe."

That dream, howver, has long since fallen by the wayside, and the reluctance of EEC countries to surrender any of their sovereignty has paralyzed the Eurocrats' work.

Some EEC officials, with their proposals in a hopeless state of limbo until member countries reach a verdict, are faced with literally nothing to do for months, and even years.

"With all that spare time, I can read what I like and think about new ways to spend my money," one Common Market official remarked.

For EEC officials with a college degree and no experience, basic salaries start at $26,200. A senior staffer with a few years experience can take home an annual paycheck that reaches a cool $85,000.

At the pinnacle of pay and authority, EEC Commission President Roy Jenkins makes about $120,000 a year, tax free.

No national taxes are assessed and an "expatriate bonus" of 16 per cent of salary is given to those hired outside Belgium. All salaries are indexed to inflation rates and furthermore jobs are granted according to nationality making it virtually impossible to be fired for incompetence.

Generous perquisites flesh out the salary scale. Marital partners and children are subsidized - 5 per cent of basic salary for the spouse and $1,500 dollars a yeaf for each child under 26. Schooling costs are defrayed and each new birth is rewarded with a $250 bonus for the Eurocrat.

The list of fringe benefits seems endless. Insurance provides five times an employee's salary upon his death. Unlimited sick leave is available and medical expenses are fully reinbursed. Moving and "installation" expenses are also covered, with costs often exceeding several thousand dollars to settle a new Eurocrat.

The Common Market's own supermarket allows its employees to buy such staples as filet mignon, caviar, smoked salmon and champagne at a 25 per cent discount. Cars can be purchased tax free, with special license plates marked by a "EUR" encircled by stars to intimidate traffic police.

Middle-level secretaries earn salaries of $18,860, more than corporate managers of many British firms. Recently, an Irish chauffeur staged a one-man protest at EEC headquarters claiming that his lucky colleagues who drove Common Market limousines pocketed more than the Irish prime minister.

Inevitably, this "mother lode" for bureaucrats has spawned its share of abuses, as well as thriving entrepreneurs.

One Eurocrat was nabbed in the curious "case of the missing doors." For several weeks, a number of doors disappeared from EEC offices. After security police traced them to a staffer's country headquarters with a few friends dressed in overalls and installed them in his opulent house.

Two Italians working as doormen at the Common Market pass the time by running a popular Italian restaurant across the street. In their leisure hours, they operate a lucrative trade in olive oil.

It is said, however, that the ultimate method of turning a handsome profit at the Common Market is by qualifying for what is known as "the golden handshake," which is considered the most civil, and expensive, way ever designed to fire unwanted employees.

Redundant Eurocrats are offered 90 per cent salary fo the first six months, 70 per cent for the next five years, and 60 per cent until the official reaches the age of 60, when the generous EEC pension program takes over.

Some present Common Market bureaucrats are anxiously awaiting the day when Greece, Spain and Portuguese enter the community. That wave of expansion, expected in the early 1980s, will hasten the departure of hundreds, if not thousands, of EEC staffers to create space for new arrivals from the three Mediterranean countries.

"You can bet I'm going to try to take advantage of that event. It will mean my life is paid for, I will have all the time I need to devote to new interests, and no more boring days in that place," signed an EEC official, nodding toward the 13-story, glass-and-steel building that encases the rich, but poor Eurocrats.