The Consumer Financial Protection Bureau on Wednesday issued a series of proposals to create more flexible repayment plans for the millions of Americans struggling with private student loans.

Such loans, which are offered by banks and other financial firms, account for $150 billion of the $1 trillion in outstanding student loan debt, but they have come under increased scrutiny. They generally carry higher interest rates and fewer protections than federal loans, and borrowers are rarely afforded wiggle room when they can’t afford minimum payments.

To ease the burden on borrowers, the consumer bureau said that those who pay on time should be able to refinance their debt at lower interest rates. Borrowers who fall behind should have access to income-based repayment plans, it said. The CFPB urged lenders to implement those recommendations. In addition, it said policymakers should help those with private loans by replicating for them the rehabilitation program available to those with federal student loans, which helps people exit default and repair their credit.

“Many private student loan borrowers have run out of options and are struggling to make ends meet,” CFPB Director Richard Cordray said Wednesday at a hearing in Miami. “Student debt has become the defining feature of their lives — the millstone around their necks that holds them back from a full financial future.”

The CFPB’s proposals are based on input from nearly 30,000 borrowers, policy experts and lenders. It follows a report the agency issued to Congress last year noting that lax underwriting standards crept into the private student loan market in the run-up to the financial crisis. Just 60 percent of private loans originated in 2006 and 2007 had co-signers, compared with 90 percent in recent years. The effects of those loans weren’t felt until students left school and were confronted with unmanageable debt in a tough employment market, according to the CFPB report.

“Lenders have to consider the possibility that borrowers won’t graduate or find a job with a salary that allows them to meet their monthly payment,” Rohit Chopra, student loan ombudsman for the CFPB, said during a call with reporters Wednesday.

He added, “Many borrowers get a good job, though, and have been making good on their promises to pay, but they simply can’t find a refinance option.”

The lenders that dominate this market, including Citigroup, JPMorgan Chase, Wells Fargo and Discover Financial Services, are less likely to restructure loans by lowering or delaying the payments, according to the bureau.

Part of the problem, industry groups say, is that accounting rules would require banks to set aside more capital before making those types of concessions.

“It’s important to recognize that these student loans are very unique assets and the characteristics are very different than other types of loans,” said Pace Bradshaw, vice president of congressional affairs at the Consumer Bankers Association, whose members include private student lenders.

The association recently sent a letter to the three banking regulators asking them to give lenders more leeway to offer forbearance to recent graduates. Bradshaw pointed out that despite the hardships borrowers face, private student loans have a 5 percent default rate, compared with a 13 percent default rate for federal loans.

Still, lawmakers are pushing for industry reforms. Last month, five Democratic senators, including Sens. Richard Durbin of Illinois and Elizabeth Warren of Massachusetts, urged banks and regulators to take action to reduce the number of student loan borrowers at risk of default. Rep. Karen Bass (D-Calif.) has introduced legislation to allow private student loan borrowers to convert their debt into federal loans.

“Washington talks a lot about not passing debt onto the backs of future generations,” Bass said. “If we do nothing to respond to this crisis, we do so at our own peril because we are tying the hands of future generations from investing in our economy.”