There is growing concern over the bail-out's cost to the taxpayer
US lawmakers have expressed strong scepticism about a bail-out of the banking system, following a five-hour Senate hearing on the rescue plan.
Treasury Secretary Henry Paulson told the banking panel that delaying the $700bn (£382bn) bail-out would put the entire US economy at risk.
Lawmakers say they want assurances that the plan will benefit ordinary American home-owners as well as Wall Street.
Some have gone further, calling the plan a potential waste of public money.
"Without question, our markets and financial institutions need serious attention," said the leading Republican on the Senate Banking Committee, Richard Shelby.
"I do not believe, however, that we can solve this crisis by spending a massive amount of money on bad securities."
Committee chairman Chris Dodd, a Democrat, called the package "unacceptable" in its present form.
The White House has called on Republicans and Democrats to work together to approve the plan, under which a federal fund could buy bad debt from financial institutions with "significant operations in the US".
The fund would aim to sell off these mortgage-related debts in the future when, the Treasury says, their value might have risen.
The best protection for the taxpayer... is to have this work
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