The Federal Reserve’s attempt to push aid into the heart of the US economy is being blunted by banks struggling to process mortgage applications fast enough, keeping rates on home loans elevated, according to the largest lenders.

The Fed announced last week that it would buy mortgage-backed securities in another round of quantitative easing — nicknamed QE3.

This was partly designed to ease further the cost of mortgages, but bankers say the impact will be limited by a dearth of loan officers with banks reluctant to cut mortgage rates without the staff to process any increase in business.

“In the very near term [QE3] has virtually no transfer mechanism whatsoever to the customer,” said one executive at a leading lender, who requested anonymity. “Originators are massively backlogged in terms of origination volumes.”