President Barack Obama on Saturday slammed Wall Street's audacity for fighting a bailout fee he wants to slap on financial firms and said his Republican opponents had sided with big banks.

With Obama's popularity hovering around 50 percent and congressional elections in November, the White House wants to cast itself alongside ordinary Americans while branding Republicans as the party for the rich.

Like clockwork, the banks and politicians who curry their favor are already trying to stop this fee from going into effect, Obama said in his weekly radio and Internet address.

We're not going to let Wall Street take the money and run. We're going to pass this fee into law, Obama vowed after proposing a levy to raise up to $117 billion over the next 10 years to recoup projected losses on a taxpayer bank bailout.

A number of the banks have already repaid capital they received under the $700 billion bailout, called the Troubled Asset Relief Program, which was conceived in 2008 by Obama's predecessor, Republican George W Bush.

They complain they are being penalized unfairly for losses mainly run up by U.S. automakers and insurer American International Group, which was rescued in September 2008. Some Republicans warned the fee would be dumped on customers.

President Obama's plans to institute a 'financial crisis responsibility fee' to recoup the bailout funds from major banks is nothing more than another tax on the American public, said Republican National Committee Chairman Michael Steele.

Tapping into public rage over Wall Street excess, Obama said the money owed taxpayers paled beside the riches banks plan to pay themselves after the government rescued financial markets in 2008 and early 2009.

If the big financial firms can afford massive bonuses, they can afford to pay back the American people. Those who oppose this fee have also had the audacity to suggest that it is somehow unfair, he said.

The very same firms reaping billions of dollars in profits, and reportedly handing out more money in bonuses and compensation than ever before in history, are now pleading poverty. It's a sight to see.

Linking the fee with his administration's goal of financial regulatory reform that it says is needed to prevent a repeat of the crisis, Democrat Obama also sought to channel public anger over the bailout toward the Republican Party.

The industry has even joined forces with the opposition party to launch a massive lobbying campaign against common-sense rules to protect consumers and prevent another crisis, he said.

(Reporting by Alister Bull; Editing by Peter Cooney)