With a record amount of commercial real-estate debt coming due, some of the country's biggest property developers have become the latest to go hat-in-hand to the government for assistance.

They're warning policymakers that thousands of office complexes, hotels, shopping centers and other commercial buildings are headed into defaults, foreclosures and bankruptcies. The reason: according to research firm Foresight Analytics LCC, $530 billion of commercial mortgages will be coming due for refinancing in the next three years -- with about $160 billion maturing in the next year. Credit, meanwhile, is practically nonexistent and cash flows from commercial property are siphoning off.

Unlike home loans, which borrowers repay after a set period of time, commercial mortgages usually are underwritten for five, seven or 10 years with big payments due at the end. At that point, they typically need to be refinanced. A borrower's inability to refinance could force it to give up the property to the lender.

A recent letter sent to Treasury Secretary Henry Paulson, and signed by a dozen real-estate trade groups, painted a bleak scenario: "Right now, we believe there is insufficient systemic capacity to refinance expiring, performing commercial real-estate loans," said the letter. "For many borrowers, [credit] simply is not available," the letter noted.

To head off some of the impending pain, the industry is asking to be included in a new $200 billion loan program initially created by the government to salvage the market for car loans, student loans and credit-card debt. This money is intended to go directly to help investors finance purchases of securities backed by these assets. If commercial real estate is included, banks might have an incentive to make more loans to developers since they'd be able to repackage and sell them more easily to investors with the assurance of government backing.