The surprise order is the latest step in a long effort by Stephen Miller, the president’s top immigration adviser, and others in the administration, to limit what they consider the financial burdens of allowing immigrants into the United States.

After years of effort by Mr. Miller, the administration issued a regulation in August that would allow officials to deny permanent legal status to immigrants who are poor. The regulation, which imposes an aggressive wealth test on legal immigrants, has faced several legal challenges but will go into effect on Oct. 15 unless it is blocked by a court.

That policy, known as the “public charge” rule, says immigrants seeking to live permanently in the United States could be denied if officials deem it is likely they will be a burden on society by, for example, being unable to pay for health care or seeking food and housing assistance.

Under the new proclamation, which was earlier reported by The Wall Street Journal, officials are directed to use a similar approach in determining whether to grant immigrant visas to people seeking to live in the United States.

Immigration advocates were taken aback by the proclamation, noting there are already several steps that applicants for a green card must take to qualify, including passing background checks and health examinations.

Elizabeth Jamae, an immigration lawyer at Pearl Law Group in San Francisco, said she doubted the assertion in the proclamation that lawful immigrants were about three times as likely as United States citizens to lack health insurance.

“Most people who are receiving green cards already have a job waiting or have a spouse that is employed,” Ms. Jamae said. “When you apply for a green card you already have to meet certain financial requirements.”