The temporary suspension of H-1B and other non-immigrant visas by President Donald Trump will "disproportionately" impact high-skilled workers from Asia as well as harm the American businesses that rely on immigrant workers, US lawmakers have said.

In a huge blow to Indian IT professionals eyeing the US job market, Trump signed a proclamation on Monday suspending the most sought-after H-1B visas along with other types of foreign work visas until the end of 2020 to protect American workers in a crucial election year. The new restrictions take effect from Wednesday.

"This (the suspension of visas) will disproportionately impact high-skilled workers from Asia, who overwhelming utilise the H1-B visa system and account for over 80 per cent of H1-B visa holders in the United States," Congresswoman Judy Chu, chair of the Congressional Asian Pacific American Caucus, said on Tuesday.

The H-1B visa is a non-immigrant visa that allows US companies to employ foreign workers in specialty occupations that require theoretical or technical expertise. The technology companies depend on it to hire tens of thousands of employees each year from countries like India and China.

"It's a purely xenophobic and bigoted agenda that actually works against our national interest," Chu said.

She underlined that immigrants are vital to the US economy and are needed not only in the agriculture and medicine sectors, but also in business, academia, and "everything in between as well".

"If we want to rebuild our economy in the wake of the COVID-19 pandemic, we cannot close ourselves off from immigrants. The President's order puts his own election-year politics over the needs of our country," Chu said.

"Worse, by stoking xenophobia and furthering the false impression that immigrants take away American jobs, the President's order is putting immigrants at risk at a time when hate crimes are spiking. This order divides our country at a moment when we need to be rebuilding. I'm strongly opposed to the Trump administration's continued attacks on our legal immigration system," she said.

According to Congressman Jerrold Nadler, Chairman of the House Judiciary Committee, the visa suspension order is both an "abuse" of the president's executive power and a "politically motivated" attempt to shift blame.

Trump's "relentless anti-immigrant agenda is not only immoral, it harms the American businesses that rely on immigrant workers", he said.

The visas which are temporarily suspended include L-1 visas for intracompany transfers, H-1Bs for workers in specialty occupations as well as the H-4 visa for spouses, H-2Bs for temporary non-agricultural workers and most J-1 visas for exchange visitors.

The new rules would apply only to those who are outside the US, do not have a valid non-immigrant visa and an official travel document other than a visa to enter the country.

In a joint statement, Nadler and Immigration and Citizenship Chair Zoe Lofgren said Trump is once again abusing the law in an attempt to distract the American public from his abject failure to combat COVID-19.

"Rather than leading us into a stable period of economic recovery -- one that brings real, sustainable jobs to the American public -- he tries to shift blame and return to his favourite political ploy of targeting and scapegoating immigrants," said the two Democratic Congressman.

Congresswoman Anna G Eshoo said the president's decision unfairly blames immigrants for America's cascading economy and will only harm the nation's long-term economic recovery, growth and competitiveness.

"I represent the heart of Silicon Valley, which leads the world in innovation. Nearly one in three of my constituents was born outside of the US and they are essential to our nation's success," the Democratic lawmaker said.

Congressman Filemon Vela said the suspension will affect high-skilled workers, seasonal workers, spouses of high-skilled immigrants, researchers, scholars, and company executives seeking to transfer to the US from positions abroad with the same employer.

Noting that immigrants are essential to positive economic growth in the US, he said, "Texas alone is home to about 10 per cent of all green card holders...the state will likely be impacted the hardest after New York.Experts predict the long-term ramifications of this decision will not only stifle the nation's ability to attract top global talent, but also hurt America's greatest asset its diversity."

A green card, officially known as a Permanent Resident Card, allows a foreigner to live and work permanently in the United States.

Meanwhile, Congressman Mo Brooks praised Trump's action.

I'm also pleased President Trump refused to cave to intense pressure from the US Chamber of Commerce and other special interest groups that, out of greed and self-interest, had the hutzpah to demand the importation of even more cheap foreign labour despite the severe damage done to struggling, jobless American families, he said.

Congressman Lance Gooden said H-1B visas and similar guest worker programmes are unnecessary when 45 million Americans are out of work due to the coronavirus pandemic.

While defending his move, President Trump had noted that the overall unemployment rate in the US nearly quadrupled between February and May of 2020 -- producing some of the most extreme unemployment rates ever recorded by the Bureau of Labour Statistics.

While the rate of 13.3 per cent unemployment in May reflects a marked decline from April, millions of Americans remain out of work.