WASHINGTON — If you’re on federal disability payments and on social media, be careful what you post. Uncle Sam wants to watch.

The Trump administration has been quietly working on a proposal to use social media like Facebook and Twitter to help identify people who claim Social Security disability benefits without actually being disabled. If, for example, a person claimed benefits because of a back injury but was shown playing golf in a photograph posted on Facebook, that could be used as evidence that the injury was not disabling.

“There is a little bitty chance that Social Security may be snooping on your Facebook or your Twitter account,” Robert A. Crowe, a lawyer from St. Louis who has represented Social Security disability claimants for more than 40 years, said he cautioned new clients. “You don’t want anything on there that shows you out playing Frisbee.”

In its budget request to Congress last year, Social Security said it would study whether to expand the use of social media networks in disability determinations as a way to “increase program integrity and expedite the identification of fraud.”

Since then, administration officials said, the White House has been actively working with Social Security to flesh out the proposal, in the belief that social media could be a treasure trove of information about people who are applying for or receiving disability benefits.

Some members of Congress, like Senator James Lankford, Republican of Oklahoma, and some conservative organizations, like the Heritage Foundation in Washington, have supported the idea as part of a broader effort to prevent the payment of disability benefits to people who are able to work.

But advocates for people with disabilities say the use of social media in this way would be dangerous because photos posted there do not always provide reliable evidence of a person’s current condition.

“It may be difficult to tell when a photograph was taken,” said Lisa D. Ekman, a lawyer who is the chairwoman of the Consortium for Citizens with Disabilities, a coalition of advocacy groups. “Just because someone posted a photograph of them golfing or going fishing in February of 2019 does not mean that the activity occurred in 2019.”

Moreover, people are more likely to post pictures of themselves when they are happy and healthy than when they are in a wheelchair or a hospital bed.

More than 10 million people receive Social Security disability insurance benefits totaling more than $11 billion a month. Beneficiaries have paid into the system through payroll taxes.

President Trump is expected to detail several proposals to combat fraud in the program in his 2020 budget, to be issued on Monday.

Before he was an official presidential candidate, Mr. Trump said he would not cut Social Security.

When he announced his candidacy in June 2015, Mr. Trump maintained that position: “Save Medicare, Medicaid and Social Security without cuts. Have to do it. Get rid of the fraud. Get rid of the waste and abuse, but save it.”

But his budgets in the last two years have proposed reductions in the disability insurance program, which has been part of Social Security since 1956.

The president’s budget director, Mick Mulvaney, who is now also the acting White House chief of staff, has suggested that Mr. Trump’s campaign commitment does not cover disability benefits.

“Do you really think that Social Security disability insurance is part of what people think of when they think of Social Security?” Mr. Mulvaney asked on CBS’s “Face the Nation” in 2017. “I don’t think so. It’s the fastest growing program. It was — it grew tremendously under President Obama. It’s a very wasteful program, and we want to try and fix that.”

Brian C. Blase, a special assistant to the president for economic policy, has been coordinating development of the new proposals on Social Security. In 2014, Mr. Blase provided the staff work for a subcommittee investigation of the disability program led by Mr. Lankford, who was then a member of the House. Soon after he got to the Senate, Mr. Lankford proposed legislation to expand the use of “evidence obtained from publicly available social media.”

Mick Mulvaney, President Trump’s acting chief of staff and budget director, has suggested that most people do not think of disability insurance as part of Social Security.CreditDoug Mills/The New York Times

At present, disability examiners do not routinely look at social media. They can refer suspicious cases to the inspector general for Social Security, who may use social media to corroborate information from other sources in fraud investigations conducted with state and local law enforcement agencies.

The Trump administration contends that it could authorize greater use of social media by regulation, without action by Congress. Under pressure from the White House, Social Security has drafted a timeline that envisions publication of a final rule in the spring of 2020.

Michael J. Astrue, the last Senate-confirmed Social Security commissioner, has expressed misgivings about the idea.

“Social media sites are not exactly clear and reliable evidence,” Mr. Astrue, who stepped down six years ago, said at a Senate hearing in 2012. “Facebook puts up phony websites under my name all the time.”

That, he said, is “why you need professionally trained fraud investigators” to evaluate the information.

Few would say that the Social Security disability program was free of fraud. The government has secured guilty pleas from a number of people who concealed the fact that they were working in various industries while drawing Social Security disability benefits.

In one case, a 57-year-old Louisiana man pleaded guilty last month to theft of government funds. He had received $2,177 a month in benefits — a total of $242,000 — while employed by companies that did demolition work and job site cleaning. He also operated heavy construction equipment. He told federal investigators that the companies had been registered in the names of family members, rather than his own name, “so y’all wouldn’t find out about it,” according to court records.

In its latest financial report, Social Security estimated that it made $3.4 billion in overpayments to disability insurance beneficiaries in 2017, in part because of their failure to report work activities.

The program has been “riddled with problems, including fraud and abuse,” said Rachel Greszler, a research fellow at the Heritage Foundation. When people who can work collect benefits, she said, “it drains the system for those who truly cannot work and support themselves.”

The administration’s focus on fraud comes as the number of Americans seeking Social Security disability benefits is plunging. The number of applications was down 29 percent last year from a peak of 2.9 million in 2010.

A growing economy with strong demand for workers is one reason for the decline, officials say. In addition, they speculate that with new technology and the potential for teleworking, it is possible for some people to take jobs even though they have medical conditions that would have precluded work in the past.

Social Security officials are considering other changes that could make it more difficult for people to qualify for benefits.

They are working with the White House to overhaul the way Social Security weighs various “vocational factors” — age, education and job experience — in deciding whether a person is able to work.

In November, Social Security proposed a new rule that would strip applicants and beneficiaries of their right to an in-person hearing before an administrative law judge, after some judges came under scrutiny for leniency in allowing disability claims. In 2017, a former administrative law judge for the Social Security Administrationpleaded guilty for his role in a scheme to fraudulently obtain more than $550 million in federal disability payments for thousands of claimants.

Under the November proposal, Social Security could hold the hearings by video conference even if a claimant objected. With video conferencing, the agency said, it could improve service to the public and reduce wait times. At present, it said, nearly 860,000 people are waiting an average of 19 months for hearings to appeal the denial or termination of benefits.

But top Democrats responsible for Social Security policy in Congress denounced the proposal in a letter to the acting Social Security commissioner, Nancy A. Berryhill.

“This change would deprive millions of Americans of their constitutional right to due process and result in hearings which are less fair and less efficient,” said the letter, signed by Representative Richard E. Neal of Massachusetts, the chairman of the Ways and Means Committee, and Senator Ron Wyden of Oregon, the senior Democrat on the Finance Committee, among others.

A version of this article appears in print on March 11, 2019, on Page A13 of the New York edition with the headline: Collecting Disability? Uncle Sam May Not Be a Friend on Social Media.