(Updates prices, rewrites throughout)

NEW YORK, Feb 10 (Reuters) - Credit default swaps on U.S. banks widened on Tuesday as U.S. Treasury Secretary Timothy Geithner unveiled a plan to rescue stricken banks, with swaps on Citigroup (C.N: Quote, Profile, Research) leading the weakness.

Geithner unveiled a revamped rescue plan to cleanse $500 billion in spoiled assets from banks' books and support $1 trillion in new lending through an expanded Federal Reserve program.

The U.S. Senate, meanwhile, is scheduled to hold a final ballot on the stimulus bill, now priced at $838 billion, at noon (1700 GMT).

Citigroup's (C.N: Quote, Profile, Research) swaps were 25 basis points wider on the day at 285 basis points, or $285,000 per year for five years to insure $10 million in debt, after earlier tightening by around 3 basis points, said a trader.

Bank of America's (BAC.N: Quote, Profile, Research) swaps also jumped by 15 basis points to around 172.5 basis points.

"People want to be hopeful, but it's going to be a seesaw," Ricardo Kleinbaum, analyst at BNP Paribas in New York, said before Geithner's speech.

"The one element of the plan that's crucial here is the good bank/bad bank, how they're going to execute it and if its real," he added.

The Treasury plan includes establishing a Public-Private Investment Fund designed to entice investors to buy distressed assets.