U.S. President Donald Trump's administration on Monday unveiled a new rule that could deny visas and permanent residency to hundreds of thousands of people for being too poor.

The long-anticipated rule, pushed by Trump's leading aide on immigration, Stephen Miller, takes effect Oct. 15 and would reject applicants for temporary or permanent visas for failing to meet income standards or for receiving public assistance such as welfare, food stamps, public housing or Medicaid.

Such a change would ensure that immigrants "are self-sufficient," in that they "do not depend on public resources to meet their needs, but rather rely on their own capabilities, as well as the resources of family members, sponsors, and private organizations," said a notice published in the Federal Register.

"The principle driving it is an old American value, and that's self-sufficiency," Ken Cuccinelli, acting director of U.S. Citizenship and Immigration Services, said in a Fox News interview published on Monday.

"It will also have the long-term benefit of protecting taxpayers by ensuring people who are immigrating to this country don't become public burdens, that they can stand on their own two feet, as immigrants in years past have done," he said.

Acting director of U.S. Citizenship and Immigration Services Ken Cuccinelli says the move will protect U.S. taxpayers. (Evan Vucci/The Associated Press)

U.S. House majority leader Steny Hoyer called the move "counterproductive" and warned in a statement that it would deter potentially "great future Americans" from coming to the U.S.

"The Trump administration ... is trying to shut down the new ideas, new labour and new entrepreneurship that immigrants bring."

Immediately after the rule was announced, the National Immigration Law Center (NILC) said it would file a lawsuit to stop it from taking effect. The group's executive director said the rule was racially motivated, with the group's Twitter account alleging the administration is seeking to redefine the legal immigration system "to disenfranchise communities of colour and favour the white and wealthy."

The overhaul is part of Trump's efforts to curb both legal and illegal immigration, an issue he has made a cornerstone of his presidency.

He has pledged to build a wall along the U.S. southern border with Mexico — initially saying Mexico would pay for it — and has pressed for changes to immigration laws. Both efforts have made little progress with lawmakers.

The administration has also tried to deny the right to seek asylum of those who cross into the U.S. between ports of entry, and has sought to keep increasing numbers of those who legally apply for asylum and are waiting out their cases south of the border in countries such as Mexico and Guatemala.

Most controversially, it has separated migrant children from family members who crossed between ports of entry, with several congressional hearings detailing confusion among the agencies assigned to track and reunite those families who have been separated.

Could drastically reduce green card recipients

The 837-page green card rule change on benefits could be the most drastic of all the Trump administration's immigration policies, experts have said. Advocates for immigrants have criticized the plan as an effort to cut legal immigration without going through Congress to change U.S. law.

Under the new rules, more than half of all family-based green card applicants would be denied, according to the Migration Policy Institute, a research organization. Some 800,000 green cards were granted in 2016.

Stephen Miller, shown in 2018, is considered an influential adviser on immigration policy in the Trump administration. (Evan Vucci/The Associated Press)

The new rule is derived from the Immigration Act of 1882 that allows the U.S. government to deny a visa to anyone likely to become a "public charge." Immigration officers in recent years have defined visa applicants as a public charge if they are likely to become primarily dependent on government assistance.

Most immigrants are ineligible for the major aid programs until they get green cards, but the new rule published by the Department of Homeland Security expands the definition of a public charge that stands to disqualify more people.

Applicants will now need to show higher levels of income to get a visa and the rule greatly expands the list of government benefits that would disqualify them from obtaining U.S. residency.

Immigrant advocates have expressed concern the rule could negatively affect public health by dissuading immigrants from using health or food aid to which they or their children are entitled.

The new public assistance threshold, taken together with higher requirements for education, work skills and health, would make it more difficult for immigrants to qualify for green cards, advocates say.

"Without a single change in the law by Congress, the Trump public charge rules mean many more U.S. citizens are being and will be denied the opportunity to live together in the U.S. with their spouses, children and parents," said Ur Jaddou, a former Citizenship and Immigration Services chief counsel who's now director of the DHS Watch run by an immigrant advocacy group. "These are not just small changes. They are big changes with enormous consequences for U.S. citizens."

Immigrant usage of assistance small

Green card hopefuls will be required to submit three years of federal tax returns in addition to a history of employment. And if immigrants have private health insurance, that would weigh heavily in their favour.

Active U.S. military members are exempt. So are refugees or asylum seekers, and the rules would not be applied retroactively, officials said.

In general, immigrants are a small portion of those receiving public benefits. For example, non-citizen immigrants make up only 6.5 per cent of all those participating in Medicaid. More than 87 per cent of participants are native born. The same goes for food assistance: Immigrants make up only 8.8 per cent of recipients, and more than 85 per cent of participants are native born.

The plan drew predictably opposed reaction from Democratic and Republican members of Congress, including Rep. Paul Gosar of Arizona and Rep. Chellie Pingree of Maine.

Solid work by <a href="https://twitter.com/USCISCuccinelli?ref_src=twsrc%5Etfw">@USCISCuccinelli</a> on the public charge rule. Taxpayer funded public assistance should not be an incentive to immigrate to the U.S. and we should not be giving green cards to immigrants who would rely on government welfare. —@RepGosar

The Trump admin proves yet again that cruelty is the point.<br><br>They are forcing a Sophie’s Choice on lawfully present asylum seekers + refugees—forgo food, housing assistance and medical care or lose all hope of obtaining a green card + reuniting w/ family.<a href="https://t.co/lZtgcByZFb">https://t.co/lZtgcByZFb</a> —@chelliepingree

Other parts of the Trump administration have taken or are contemplating similar approaches to penalize immigrants' use of public assistance.

The State Department changed its foreign affairs manual in January 2018 to give diplomats wider discretion in deciding visa denials on public-charge grounds. In the 2018 fiscal year, which ended last September, the number of visas denied on those grounds quadrupled compared to the previous year.

The Justice Department also is considering a regulation that would dramatically expand the category of people who could be subject to deportation on the grounds they use public benefits.