Many U.S. tech companies are pushing hard this year for an increase in the number of high-skill immigrants allowed into the country, but many veteran IT workers question their motives for wanting to increase the number of visas under the controversial H-1B program.

Microsoft, IBM and recently Facebook are among the large tech companies that have called for an annual increase in H-1B visas for high-skill workers, arguing they can't find qualified tech workers in the U.S. to fill all their open positions. Reports from those companies -- and others -- of thousands of unfilled tech jobs in the U.S. seem to support their argument.

A group of eight U.S. senators has pushed this year for an increase from the current 65,000-person cap on H-1B visas to as much as 300,000 workers. But critics say the skilled worker visa program undercuts U.S. wages and is filled with abuse.

Many tech companies arguing for higher H-1B caps also say the U.S. should be encouraging the world's top IT talent to come to the U.S. "Why do we offer so few H-1B visas for talented specialists that the supply runs out within days of becoming available each year, even though we know each of these jobs will create two or three more American jobs in return?" Facebook CEO Mark Zuckerberg wrote in an April blog post. "Why don't we let entrepreneurs move here even when they have what it takes to start new companies that will create even more jobs?"

It's unclear if companies calling for the U.S. Congress to bump up the skilled immigration numbers will get their wish. Many lawmakers prefer to deal with skilled immigration issues at the same time as they deal with the contentious larger debate on illegal immigration. But this month, Senate Judiciary Committee Chairman Patrick Leahy, a Vermont Democrat, said immigration reform will be a priority in the coming months.

Many U.S. tech companies say an increase in the cap is needed.

stock photo Rick McNeight

Modus Operandi, a semantic search software vendor based in Melbourne, Florida, has had "a hell of a time trying to fill these positions," said Rick McNeight, the company's president.

The 80-person company has six open positions, three for Java programmers, with those positions open for months, McNeight said.

Data from Dice, the tech job board, CareerBuilder and staffing agency Kelly Services show thousands of open IT jobs across the U.S., with significant openings in application development, including mobile apps and HTML 5, IT infrastructure support, and for IT project managers. Java and .Net developers are in high demand, said Melisa Bockrath, vice president and group leader for the IT unit of Kelly Services.

CareerBuilder, the online job-search portal, had more than 290,000 job listings for application developers between December and February, and just over 20,000 active candidates in related fields. AT&T and IBM each had more than 3,400 app developer job postings during that three-month period; Microsoft and Computer Sciences each had more than 1,250 postings.

CareerBuilder listed more than 30,000 IT project management jobs during the same time period. There were about 5,500 active job seekers in that area.

But only 15 percent of the active candidates in the app developing field, and 11 percent in IT project management, said they were willing to relocate for a job.

The picture is more complicated than the stats suggest. Many veteran IT workers, some with close to 20 years of experience, say many U.S. tech vendors don't want their services.

Many U.S. tech companies want more H-1B visas so they can hire cheaper foreign workers, contrary to the official stance that tech companies want to bring the most talented tech workers to the U.S., some critics say. (See related story: Veteran tech workers see tough job market.)

Foreign visas are a large part of the problem for veteran IT workers, said John Donaldson, a 51-year-old software developer out of work since October. "I blame much of my misfortune on the H-1B visas flooding this country," he said. "When I picked my computer science major ... no one told me I'd be competing against a huge tide of foreign nationals flooding, via dubious means, the national job market every year."

stock photo Melissa Bockrath

In some cases, the out-of-work IT veterans have a skills mismatch with the jobs available, said Bockrath, of Kelly Services. Many companies want experience in their field; companies believe that developing apps for the oil and gas industry is different than developing mortgage apps for a bank, she said

In other cases, candidates aren't willing to move for a job, said Bockrath, whose company partners with CareerBuilder to look at hiring trends. Veteran tech workers living in areas of high unemployment "need to be a little more flexible" about relocating, she said.

Many of Kelly's corporate clients are having trouble recruiting IT workers, she said. In areas with IT worker shortages, Bockrath has advised clients to consider remote workers, in the jobs that lend themselves to telework, she said.

Many companies aren't focused on retraining older workers, said Bill Peppler, managing partner at staffing firm Kavaliro. "I'd love to see companies take a shot on people who were retrained," he said.

Peppler sees worker shortage, but he believes more H-1B visas would be a short-term fix. In the long-term, the U.S. needs to focus more on developing its own science and technology workers, he said. "It's a shame we don't have enough talent in the states to meet demand," he added.

For McNeight, of Modus Operandi, more foreign visas would, at best, have an indirect impact on his ability to hire workers. Because his company works with the U.S. military and intelligence agencies, most of his programmers need security clearances. More H-1Bs might fill open positions at other companies, making it easier for him to recruit, he said.

Within the last two weeks, DataStax, a San Mateo, California, big-data applications vendor, had about 15 open positions, including Cassandra engineer, QA engineer, and product manager. The 80-person shop wants to hire 160 people in 2013.

CEO Billy Bosworth said he's turned to recruiting foreign workers and offering them telework jobs in an effort to close hard-to-fill positions. More H-1B visas would be helpful to companies like DataStax, he said.

Many U.S. IT workers with hot skills are sick of hearing from recruiters, he said. "They've turtled up," Bosworth said. "They've gone into stealth mode."

Bosworth has also snapped up IT workers when he doesn't have an immediate job opening. "If I find a good person and I don't have an [open request], I'll hire him," he said.