WASHINGTON — Federal policymakers have rushed to backstop nearly every corner of the financial system as the coronavirus exacts a bruising toll on the U.S. economy. But there is growing concern that a critical corner of the housing industry has been overlooked, putting mortgage companies in a precarious position as millions of borrowers delay payments.

The strain is expected to intensify in the coming weeks, as businesses shed millions of workers who will have little choice but to seek a hardship payment waiver or forbearance from their lenders. That could put a large swath of the mortgage industry in jeopardy, with firms that are not banks but make loans and collect payments facing a severe cash crunch and potential insolvency.

Lawmakers in both parties have begun warning about a looming crisis and are urging the Federal Reserve chair, Jerome H. Powell, and Treasury Secretary Steven Mnuchin to take swift action. This month, a bipartisan group of senators warned Mr. Mnuchin that $100 billion of mortgage payments could be delayed this year and that standalone mortgage servicers, whose annual net profits they estimated amounted to less than $10 billion combined, could become insolvent. House Democrats have echoed those concerns.

“Mortgage servicers are expected to face increased strain as millions of homeowners and renters lose jobs, are furloughed, or see reduced hours, all of which will keep them from making mortgage and rent payments, as a result of this public health crisis,” Representative Maxine Waters, the Democratic chairwoman of the House Financial Services Committee, and Senator Sherrod Brown, the top Democrat on the Senate Banking Committee, wrote in a letter this week.