One of the chief architects of U.S. financial reform will chair the House-Senate panel that hammers out the final version of the Wall Street overhaul, a spokesman for the Democratic lawmaker said on Monday.

Democratic Representative Barney Frank, chief author of the bill in his chamber of Congress, will head the panel, or conference committee.

Frank is expected to set a pro-reform tone in debate on proposals to tighten the rulebook for banks and markets after the 2007-2009 financial crisis.

Senator Christopher Dodd, who authored the Wall Street bill in his chamber, will be a member of the panel. So will fellow Democrat Senator Blanche Lincoln, another reform proponent, Senate aides said, amid speculation on Capitol Hill over the panel's membership, timing and format.

Republican senators Richard Shelby and Saxby Chambliss, who voted against financial reforms, will be named to the panel as well, a Senate aide said.

As the next step in a year-long reform push, the House-Senate conference will be crucial in determining the final shape of legislation.

Banking interests are digging in for a last attempt to water down the bill and carve out loopholes for themselves.

U.S. financial stocks did not react on news of the panel positions.

The Senate approved a Wall Street reform bill last week. It must now be merged with one approved by the House of Representatives in December. The end-product promises to be the biggest overhaul of financial regulation since the 1930s.

The panel will have to tackle controversial proposals that banks oppose, such as Lincoln's plan to force banks to spin off their swap-trading units into affiliates, and one favored by other Democrats on curbing banks' proprietary trading.

The Senate is expected to name its conference committee members on Monday evening.

House Speaker Nancy Pelosi has the responsibility for naming the members of the panel from the House. She may wait until the second week in June to do that, aides said.

Combining the bills will be done through a conference committee process involving appointees from both chamber. Once they agree on a bill, then it would have to be approved by the House and Senate before going to President Barack Obama. He would then sign it into law.

Frank has said the conference may take about a month.

House Republican Leader John Boehner, in a letter to Pelosi on Friday, called for a wide-open conference debate that is streamed live onto the Internet.

(Additional reporting by Andy Sullivan, Kevin Drawbaugh, Roberta Rampton, Charles Abbott. Writing by Kevin Drawbaugh; Editing by Andrew Hay)