Operation Hope founder John Bryant warned that residents will have to pay car loans without cars, home loans without homes and credit card bills without jobs.
"You're going have to learn to swim in deep financial waters pretty quick," Bryant said.
Blanco called the financial crises facing many Louisiana families the "second stage" of the disaster, and said it has been one of her top concerns.
"A lot of people lost jobs, lost homes … lost everything about normal life, and the banks are going to come calling," Blanco said. "We think we can stave off foreclosure notices."
The federal government told banks to postpone debt collection for 90 days after the hurricanes, but that free period is about to expire, Bryant said at the news conference.
Louisiana's Commissioner of Financial Institutions John Ducrest said federal banking oversight agencies are likely to ask institutions to continue making exceptions for hurricane victims, but on a case-by-case basis.
"They're talking about this very issue," Ducrest said. He added he doesn't think banks are likely to issue another blanket forbearance.
Operation Hope also has $500,000 earmarked for grants to the uninsured or under-insured who are rebuilding, provided they qualify. The grants top out at $3,000 per family, and more than 400 people have already applied for the limited funds. The group wants to raise another $2.5 million for grants.
The non-profit Operation Hope Inc. was founded following the Los Angeles riots in 1992. The group helped residents rebuild following disasters including the Sept. 11, 2001, World Trade Center attacks and Florida's busy hurricane season, Bryant said.