Senate Majority Leader Mitch McConnell, R-Ky., said on CNN's "State of the Union" the Democratic-backed measure would allow bailouts of giant Wall Street financial institutions.
McConnell's comments came a day after President Barack Obama criticized him because he "made the cynical and deceptive assertion that reform would somehow enable future bailouts when he knows that it would do just the opposite."
"There is a bailout fund in the bill that was reported out of the Banking Committee, the partisan bill that came out of committee on a party-line vote," McConnell told CNN. "I don't think that's in dispute."
Brown, speaking on CBS's "Face the Nation" Sunday, said he would filibuster financial regulatory reform legislation in its present form because the "bill is not a good bill, period."
"I think the president's political arm is now taking over this debate," Brown said. "It's unfortunate because I, like many others in my state and throughout the country, want banks to be banks. I don't want them to be casinos and take risky bets on our money. I think that this is an issue that we can clearly come to common ground on and just solve the problem."
Treasury Secretary Timothy Geithner said he believed the measure ultimately would receive GOP votes and win passage.
"I am very confident that we're going to have the votes for a strong package of financial reforms that will bring derivative markets out of the dark, help protect taxpayers from having to fund future bailouts and trying to make sure we're giving Americans some basic protections against fraud and abuse," Geithner said on NBC's "Meet the Press."
He said the reform measure would ensure more accountability on Wall Street and help prevent another financial meltdown.