The rush of US homeowners to refinance mortgages at lower rates is creating a boom in the home lending business, prompting banks to hire thousands of new employees and put them to work on extra shifts to process mountains of paperwork.

"Many of them work all day, go home and have dinner with their families, then go back to the office and put in a few more hours, because there's work to be done," said Greg Gwizdz, national sales manager of the Wells Fargo home mortgage unit.