Lawmakers have expressed doubts over some aspects of the proposal to buy up some of banks' toxic assets - boosting confidence in the sector and allowing financial firms to borrow and lend more freely with each other.
Republicans in particular are concerned about the potential bill for the taxpayer, despite president George W Bush's strong support for the plan.
The differences emerged during talks between the treasury, the president, members of Congress and both presidential candidates, John McCain and Barack Obama.
Despite this, the proposals seem likely to pass soon, with chairman of the Senate banking committee Christopher Dodd saying earlier that both sides have reached a "fundamental agreement".
Stock markets have dropped in recent days over the delay to the plan's passing - after soaring on Friday when it was originally announced.
Democratic speaker Barney Frank indicated that talks would continue today.
He also strongly criticised Republican blocks to the plan, saying that he "can't believe that [they] are going to continue to defy George Bush".