The Hubert H. Humphrey Occupational Resources Center might be taken for a mirage, an alien shimmer of technology settled like Oz here among the mean housing projects and boarded-up store fronts in the black neighborhood of Roxbury.

To the thousands of kids from nearby high schools, where simply learning to read is considered a rare achievement, it does indeed represent a kind of wizardry. Inside the new Center's sprawl of futuristic classrooms--one of the largest and best-equipped such training facilities in the nation--they get a chance to lay hands on the strangeness of delicate camera settings in a $450,000 TV studio, or punch keys on a $200,000 computer or, in a gaping indoor construction pit of sand, build the bottom of a skyscraper.

"I'd never touched nothin' like that before, something really expensive and technical," said Michael Jones, a soft-spoken 6-foot-2 12th-grader who jumped at the chance to get his basketball-playing hands on the school's new Digital and Apple computers.

Since coming to the Center, he has discovered an unsuspected aptitude in data processing and computer graphics. He has signed up with the Air Force, where he will be able to take advanced computer courses after basic training. Then, he figures he can "go anywhere."

Time was when the more ambitious kids from his neighborhood might have found low-skill jobs, with decent pay and a future, even without the Humphrey Center and without much in the way of skills or even literacy. But such jobs are rapidly disappearing, specialists say.

The Center is a $38 million experiment at the cutting edge of what is called the skills gap, a tragic paradox of critical jobs going unfilled in the nation's plants and offices at the same time precious human talents waste away in unemployment lines, or on street corners in neighborhoods like this one, at great public expense. The cost is great in dollars, greater still in the waste of human capital.

President Reagan highlighted the issue graphically, if unwittingly, at a news conference. There are plenty of jobs available for those who look, he insisted, offering as proof the fat section of help-wanted ads in his Sunday newspaper.

But the bulk of those jobs are available, of course, only for those who know how to program or repair computers, assist dentists or doctors, do accounting, speak good English, use good grammar, type 30 words per minute, or otherwise contribute to the new world of clean work.

Entry-level skill requirements in many growth industries "seem to center on one skill, and that is the key punch skill," said Paul Grogan, of Boston's Neighborhood Development and Employment Agency. "And there is an exploded demand for people who can handle themselves in an office setting . . . , who understand things like punctuality, deference, organizing, presenting themselves correctly."

Estimates of the size of the skills gap vary. There were nearly 1 million skilled jobs unfilled last year, at a time when 10 million people were counted as unemployed.

Three in four jobs of the 1980s will require technical training below the college baccalaureate level, the Bureau of Labor Statistics says. Yet more high schoolers than ever are dropping out of science and mathematics after the 10th grade, eliminating themselves from technical careers, warns a recent report by the National Science Foundation.

The changes are further polarizing the haves and the have nots. In the jobs race, more of the poor in the inner cities are being left behind as non-starters, and scattered clusters of mature blue collar workers with families and mortgages find themselves suddenly obsolete, sidelined and desperate. The problems are both occupational and geographical.

Accordingly, there is a rising chorus of debate about whether the federal government can or should intervene in this chaotic striving in ways it never has before. We have to do it, some argue, not just for "bleeding heart" reasons but to keep up with the international Joneses.

Japan, West Germany and other successful industrialized countries have not been so slow to realize the importance of training, retraining and related manpower needs in a time of rapid technological change.

Yet, even as the administration is stressing the need for a revitalized private sector and greater U.S. productivity in a competitive world, it is cutting funds for job training and education.

It now takes 8,000 hours to become a machinist with sufficient skill to build the sophisticated computerized numerical-control tools that are becoming industrial mainstays. "That's about the same amount of time as my students require to get undergraduate degrees in economics," said Barry Bluestone, economics professor at Boston College and co-author of a forthcoming book, "The De-Industrialization of America."

"We need to completely rebuild the education system from kindergarten up," he said. "The opposite is happening."

In Boston, a city at the center of a thriving computer industry in the midst of the computer age, the oldest school system in America still provides only 4 percent of the students with any computer education at all. Nationwide, there are an average of only 3.2 computers for each school district.

There are pockets of innovation around the country--in California, Minnesota, the Carolinas. But generally, American education and training falls short in fitting people for a highly technical world, some specialists say.

Having already bottomed out and begun its climb back to economic vitality, Massachusetts offers a fat sampling of the tentative couplings of businesses and schools, public and private money, now being explored.

At the Humphrey Center, for instance, the curriculum is written to a great extent by the employers who, it is hoped, will hire its graduates. Some employers have also contributed hundreds of thousands of dollars worth of equipment and people.

Michael Odom is on the payroll of the Digital Equipment Corp., a Massachusetts mini-computer pioneer. However, Odom has spent his days not at Digital but at the Humphrey Center, ever since the school opened, as "an internal consultant and broker," helping the teachers figure out the best ways to "produce kids who can either get jobs or go to college."

"I guess I'm kind of a shock troop--or a sacrificial lamb," he said with a laugh. "Until a business person gets inside a school, I don't think he can understand the positive and negative pressures. . . . We're asking the schools to do an enormous number of things."

These include providing for students who speak little or no English, for handicapped or troubled children, and for the many children from one-parent homes where there are "no computers and not much enrichment of any kind." At the same time, funds are drying up for federal manpower training programs such as CETA that relieve pressure on the schools.

The Humphrey Center is unusual in focusing on the high school level, Odom said. The high-tech industry, a largely suburban culture, so far has concentrated at the university level, while high schools have had to subsist primarily on rhetoric, says Bill Spring, president of the board of directors of the Tri-lateral Council for Quality Education in Boston, a federally funded cooperative venture of school and business officials.

"You're talking about job openings for kids with skill 'X,' and right now we're still trying to get them up to a level where they can learn that skill. We're still concentrating on teaching them the basics."

"Businesses, the schools and the city are recognizing how close the connection between school and work is as they have never done before," said Catherine Stratton of the city's Private Industry Council. "The theme is clear. If we are going to hire them . . . we have to have a public commitment from the schools that we'll get graduates who can read and write."

The PIC is setting up a program in which the major employers guarantee, say, 3,500 unsubsidized jobs if the schools will guarantee that their graduates can speak, write and compute at 12th-grade level. But that is several years down the road.

Employers are willing, and increasingly able, to provide technical on-the-job training, she said. "But employers are not going to spend their money on basic employment preparation. It's not in their interest to do it. Clearly this should be the linchpin of federal policy."

Private employers spent $800,000 for manpower training in 1981, according to city officials, and are expected to increase that to perhaps $4 million this year.

There is disagreement about which approaches work best. Most specialists seem to agree that, whatever approach is taken, the private-sector contributions will not be enough to offset cutbacks in public funds, and should not be expected to supplant the government. They recommend a mix.

They also caution against relying too much on set, rote skills based on often wrong predictions about the job market.

Jim Caradonio, new head of the Humphrey Center, holds up two newspaper articles to illustrate. Published this year, six weeks apart, one proclaims a "crisis" caused by a high-tech personnel shortage, and the next gloomily describes how the recession has caused high-tech employers to "almost stop hiring."

Given the volatility of the job market, modern workers ideally should be able to transfer their abilities quickly from one setting to another. "We are not 'training' kids. We are teaching kids to think," Caradonio said. "Give them the basics, prepare them for entry-level. The companies can train them on their own machines."

But many of the displaced blue collar workers are not able to transfer their skills into the new high-technology, high-paying jobs, according to Bluestone.

In a study of 833,000 workers in mill-based New England industries since 1957, he found that by 1975 "fewer than 3 percent were employed in high-technology industries, while five times as many went into trade or service jobs. A few made the leap to high-skill jobs, but most others became downwardly mobile."

At the same time, "lower levels of education and training of Boston resident workers (especially the growing proportion of minorities) placed them at a competitive disadvantage with suburban commuters for the better jobs," according to a recent report by city officials.

The economy used to take the form of a "mountain" of manufacturing jobs with a small number of low-skill jobs at one end and a few high-skill jobs at the other, Bluestone said. "But the middle is missing now, and we have a growing gap between high-wage and low-wage jobs."

Said the Tri-lateral Council's Spring, describing what is sometimes called the McDonald's syndrome, "The old decently paid, unskilled jobs are rapidly disappearing." Not so long ago, a kid fresh out of high school could go get a job at a plant which not only paid a decent wage but offered a chance for advancement and union protection, he said. Now, the jobs available to that same kid are likely to be "low-paid, unstable and dead-end."

Even the shiny new Humphrey Center, like most such training approaches, faces formidable obstacles.

* The Center sports a seamstress class, with dressmakers' dummies. Though the textile industry has suffered a long decline, there are still teachers who teach the subject, unions to represent them and a bureaucratic inertia that resists change, specialists said. The new director plans to replace the dummies with Apple micro-computers as soon as possible.

* The school needs a machine shop--not the old-fashioned kind; the new numerical-control machines--but it hasn't been able to afford the costly equipment and, as in many subjects, it must first retrain the teachers before they can train the students.

* The new building is referred to as a white elephant by some employment specialists in Boston because it stands empty so much of the time. The new director is fighting for enough money, he says, to keep it open evenings, and is trying to attract adult retraining classes.

* In a school system where maybe half the students drop out before graduating, this school like the others has to strive to keep its enrollment up and keep the students interested.

Still, some students who had dropped out of their regular schools, or threatened to, now have been lured back to school by the glossy promise of the Humphrey Center.

Jobs programs, especially those aimed at disadvantaged populations, have a murky record of scattered successes and considerable controversy. A sentiment heard frequently from workers in the field is the lament that the programs are being eviscerated "just as we had begun to learn what works."

The training is costly, and many of the so-called beneficiaries apparently cannot be helped at any cost. But at least some can be turned into productive workers.

The Humphrey Center, 19 months old, is too young to have much of a track record in placing its graduates in jobs. Yet as Caradonio points out, "This is it for them. There's nothing else."