WASHINGTON (CNNMoney.com) -- As the Obama administration considers how to approach the next phase of the $700 billion financial bailout, questions are being raised on Capitol Hill about whether it is helping the economy.

Treasury Secretary Tim Geithner told a congressional panel Thursday that the administration hopes to start winding down the Troubled Asset Relief Program.

Treasury officials have been talking about shutting down some TARP programs, while refocusing on areas like small business loans and mortgage modifications. TARP officially could end Dec. 31, but Treasury has the power to extend it through next fall.

"We are working to put the TARP out of its misery. And no one will be happier than I am ... to see that program terminated and unwound," Geithner told members of the Joint Economic Committee.

The hearing got heated at points, with Republican Rep. Kevin Brady of Texas asking Geithner to consider resigning, citing the struggling economy, "frightening" deficit and extensive job losses.

Also on Thursday, the Congressional Oversight Panel quizzed top economists about the bailout's effectiveness in helping to stabilize the economy.

The panel of experts said TARP helped avoid collapse of the financial system. But they also blasted TARP's design, structure and programs, and said it wasn't entirely fair or transparent.

"I think the TARP ends up being counter-productive in that it abused public faith," said Dean Baker, co-director of the Center for Economic and Policy Research. "They oversold the benefits."

And few believed it has been helpful in propping up the economy.

"Housing stability efforts have been particularly disappointing," said Mark Zandi, chief economist and co-founder of Moody's Economy.com. "And of course small business lending has not worked at all."

The panel disagreed about whether the federal bailout program ultimately made banks safer and better capitalized.

Zandi said he thought the bailout worked well for the largest banks, which he called "over-capitalized." He also said that without TARP, the nation would still be in a recession.

But Baker said he was more skeptical about the health of large banks, especially since the stress tests performed by regulators last spring didn't anticipate the current levels of unemployment.

"Not to say that they're all going to collapse, but I'm less confident of their soundness going forward," said Baker. Many banks that are doing well are making their profits on trades and not bread-and-butter banking activities, he said.

Simon Johnson, a Massachusetts Institute of Technology economics professor, said he didn't believe the economy was a "stable system," especially since the largest banks can count on the government to bail them out if they get into big trouble.

"When you have an entity like Goldman Sachs (GS, Fortune 500) that has direct access to the Federal Reserve ... and is allowed to take any kind of risky investment that they want, you're basically running a big hedge fund," Johnson said.

When asked whether TARP should be allowed to continue, the answers varied.

Alex Pollock, a fellow at the American Enterprise Institute, said he opposed extending the program.

"It is easy to imagine how much the Treasury and the administration would like to extend as long as possible the power and independent capacity they enjoy through the operation of TARP," Pollack said. "It is time to observe its target expiration date."

Johnson said he thought the bailout should be wound down, but that the money be kept in an emergency fund in case the recovery stumbles and veers back toward crisis again.

But Zandi and Charles Calomiris, a professor at Columbia University's business school, both said that TARP should be re-dedicated to helping homeowners with mortgages.

They believe that officials should abandon the current loan modification program and start a new one, where the government would give banks financial incentives to write down loan principal amounts.

"That's been the essence of what's been missing," Calomiris said. "The nice thing about that write down is it works to help marginal borrowers but not hopeless cases."