RENO, Nev. — Education Secretary Betsy DeVos has frequently been the target of angry borrowers who say her department does a bad job managing the student loans of tens of millions of people.

On Tuesday, she said the government’s $1.5 trillion student loan portfolio should be someone else’s problem.

Calling student loan financing an “untamed beast,” Ms. DeVos said it should be spun off into its own federal agency. Her department’s Federal Student Aid office is battered by “the ever-changing political whims of Washington,” she said, and “cannot fulfill its mission” in its current form.

“I’m not so sure the federal government should monopolize student lending,” she said in a speech at the start of a four-day training conference in Reno for 5,000 financial aid officers from schools nationwide. “But if it does — and, for now, it essentially does — then it must provide services on par with world-class financial firms.”