A small group of Social Security judges have improperly approved disability claims for nearly 25,000 people who didn't qualify, costing taxpayers $2 billion over the past seven years, government investigators conclude in a report being released Monday.

The price tag will grow by nearly $300 million next year because many of these people are still getting benefits, the report said.

Social Security's office of inspector general is scheduled to release a report on the judges Monday. The Associated Press obtained a copy Friday.

Investigators examined cases decided by 44 judges who had been approving disability claims at unusually high rates. The judges were labeled "outliers" because they had approved 85 percent of the claims they had heard in at least two of the previous seven years. During these years, the judges decided at least 700 cases a year.

The judges represent about 4 percent of the administrative law judges who decide disability claims for Social Security, the report said.

"The Social Security Administration's failure to conduct timely medical eligibility reviews has resulted in rubber-stamped decisions that have and will continue to cost taxpayers billions in improper awards," Rep. Darrell Issa, R-Calif., said in a statement. "In failing to take meaningful disciplinary action at the Social Security Administration, even after the most egregious cases of mismanagement, taxpayers are left to wonder, who is looking after their tax dollars?"

Issa, who chairs the House Oversight Committee, requested the inspector general's investigation, along with Rep. James Lankford, R-Okla., who chairs one of the panel's subcommittees.

The report said the Social Security Administration has improved oversight of judges in the past several years. Fifteen of the 44 judges have been disciplined, including one who was let go when his or her contract expired. None of judges were identified in the report.

The Social Security Administration did not immediately respond to a request for comment.

The report comes as Social Security's disability program edges toward the brink of insolvency. The trust fund that supports the disability program is projected to run out of money in 2016. At that point, the system will collect only enough money in payroll taxes to pay 80 percent of benefits, triggering an automatic 20 percent cut in benefits.

Congress could redirect money from Social Security's much bigger retirement program to shore up the disability program, as it has several times in the past. But that would worsen the finances of the retirement program, which is facing its own long-term financial problems.