President-elect Donald Trump’s policies on illegal immigration, particularly on the border wall and cracking down on sanctuary cities, were at the center of his election campaign. Now, advocates of immigration restriction are hoping for reform to H-1B visas that they say are hurting American workers.

The H-1B is a temporary, non-immigrant visa, currently capped at 85,000 visas a year, that allows employers to hire skilled, specialty workers on a temporary basis -- particularly scientists, engineers, or computer programmers.

However, critics say that the system is rife with abuse, and is no longer a limited short-term program to help employers with unexpected labor shortages in niche areas, and has instead become a way to push out American workers in favor of cheap foreign labor.

“Because of lobbying by the Chamber of Commerce and big tech companies, they’ve succeeded in loosening standards and we’ve seen the increasingly common scenario where American workers are fired, and have to train their replacements,”  Dan Stein, President of the Federation for American Immigration Reform, told FoxNews.com.

Trump has shifted stances somewhat on the visas. After initially taking a hard stance against them, in contrast to some of his Republican opponents, at a primary debate in March he appeared to change his stance and said: “I’m changing. I’m changing. We need highly skilled people in this country, and if we can’t do it, we’ll get them in.”

TRUMP'S BATTLE AGAINST ILLEGAL IMMIGRATION MAY END AT CHURCH STEPS

He later released a statement saying the H-1B program “is neither high-skilled nor immigration: these are temporary foreign workers, imported from abroad, for the explicit purpose of substituting for American workers at lower pay.”

“I will end forever the use of the H-1B as a cheap labor program, and institute an absolute requirement to hire American workers first for every visa and immigration program. No exceptions,” he said.

Advocates of immigration restriction have been made hopeful that a Trump administration will clamp down on the visa. In particular they have been buoyed by Trump’s decision to pick Alabama Sen. Jeff Sessions as his attorney general – known for his hardline stances on both illegal and legal immigration.

In 2015, Sessions sent round an “immigration handbook” to Republican members of Congress that calls immigration reform “a legislative honorific almost exclusively reserved for proposals which benefit everyone but actual American citizens.”

In that handbook and since, Sessions has railed against what he sees as the abuse of the program. In his handbook he cites statistics suggesting that guest workers make up two-thirds of all new IT hires, while half of Americans with STEM [Science, Technology, Engineering, and Mathematic] degrees can’t find work. He says that while the cap is 85,000, the real number is much higher.

“But, due to overlapping admissions and other factors, the total number of H-1B workers physically present in the U.S. is actually much higher—it has been estimated to fall somewhere in the range of 650,000 to 750,000,” he wrote.

While Sessions’ appointment may put those companies who use the system on edge, analysts say there is still a long way to go in appointments.

“I think companies are in wait-and see mode, By the time of inauguration there’ll be a clearer sense of who will be head of Council of Economic Advisors and the Department of Labor. There’ll be a better sense of the team and that will tell the tech companies something,” Robert D. Atkinson, president of the Information Technology and Innovation Foundation (ITIF), told FoxNews.com.

The plight of American workers being replaced was highlighted earlier this year when laid-off Disney IT workers sued the company, claiming that despite high performance ratings, they were made to train their foreign replacements. In February, the Senate Judiciary Committee heard testimony from some of those laid off. Presiding over the hearing was Sen. Jeff Sessions.

However, supporters of the program warned that while surgically reforming the program could work, cutting it too deeply could have the opposite of the intended effect, and actually hurt American workers if companies can’t get the help. They warn that some companies may actually ship more jobs overseas if the visa is limited.

“Companies doing tech work……they would be thinking about expanding work in places other than United States. They might put it in Canada, in a place like Vancouver, where Microsoft employs a lot of  people because they can find it hard to get the skills to come to the U.S.,” Atkinson said..

“The whole view that there’s not a shortage [in STEM workers], I think that’s wrong, and the idea that H-1B workers are substitutes is wrong,” he said. “They normally complement one another, allowing companies to gain global market shares and expand even more.”

Adams Nager, economic policy analyst at ITIF, found that unemployment in STEM fields is very low, and concludes that, despite occasional stories of lay-offs, “America faces a shortage of high-skilled STEM talent, especially in IT industries.”

Those opposed to the current state of the program say there are a number of things a Trump administration could do without needing whole-scale reform from Congress.

“One of those is to collect the data and make it available to the public. That would strike horror into the industry,” John Miano, a fellow at the Center for Immigration Studies, told FoxNews.com “This has been kept secret or not collected. We don’t know who are getting the visas, we don’t know where the people are, what occupations they’re in or what the salary is.”

Other possible reforms include a clarification on the definition of “specialized knowledge,” which could help cut down on abuse, and a limit on such visas for two years.

Proponents on both side of the issue agree that, despite the pick of Sessions as AG, it is not yet clear which way the administration will fall on the issue. Trump’s official website makes no mention of H-1Bs on the immigration policy page. But those who want significant reform are hopeful in the wake of the Sessions pick.

“H-1B spans the Department of Justice, Labor Department and USCIS [United States Citizenship and Immigration Services]. There’s hope you’d have people at all three levels enforcing the law, and Sessions gives us hope they’ll start doing that,” Miano said.

Adam Shaw is a Politics Reporter and occasional Opinion writer for FoxNews.com. He can be reached here or on Twitter: @AdamShawNY.