Hundreds of shops and companies across the south of England are struggling to recover from the torrential rain over the last few weeks.
NatWest and RBS have launched a 250m UK Storm Business Fund to provide short-term loans to the affected businesses.
Chris Sullivan, chief executive of the Natwest/RBS Corporate Bank, said: “We're making additional support available because we know how important it is to the local economy and communities to get these businesses operational again."
He added: “Many firms have taken a real hit to their livelihood."
Loans will be interest-free for three months, while the maximum amount available will be £250,000 per business.
The fund and support package, which can be used for repairs or to replace damaged stock, is available for all affected businesses, not just Natwest and RBS customers.
Some local authorities have also pledged money to help with Somerset County Council offering a £50,000 donation to launch an Emergency Flood Relief Fund in the area.