WASHINGTON -- Another Democrat is adding his name to a small but growing list of senators opposed to President Barack Obama 's nominee for a top Treasury Department post.

Sen. Joe Manchin (D-W.Va.) said Wednesday that he will vote against Antonio Weiss as the next undersecretary for domestic finance, the number three slot at Treasury. Weiss is currently a senior banker at financial giant Lazard.

"I cannot and will not support his nomination because I do not believe he possesses the characteristics and the background we need in an undersecretary to push for strong Wall Street oversight and to protect our small businesses and financial institutions on Main Streets across America," Manchin said during remarks on the Senate floor.

The West Virginia senator raised several concerns about Weiss, among them that his background in investment banking doesn't qualify him to oversee Wall Street reform, financing the national debt, housing finance reform or small business credit -- all responsibilities that come with the Treasury job. He also highlighted the $20 million payout from Lazard that Weiss stands to earn if he gets the government gig, something he wouldn't get if he leaves for another financial firm.

"The undersecretary should have a broad background in financial services, with the critical inclusion of community banking, which is so important to thousands of rural communities, small towns and suburbs," said Manchin. "A person with direct Main Street experience can fully appreciate the special concerns of that industry. Unfortunately, Mr. Weiss does not fit the bill, and for that reason, I must oppose his nomination."

Manchin's opposition comes hours after Sen. Jeanne Shaheen (D-N.H.) said that she will also vote against Weiss , whom Obama nominated last month. She expressed concerns about his experience in "corporate inversions," a politically toxic practice involving U.S. companies relocating their headquarters to other countries to avoid U.S. taxes. Lazard itself is based in Bermuda.

Sens. Dick Durbin (D-Ill.) and Bernie Sanders (I-Vt.) have also said they won't support Weiss. But it's Sen. Elizabeth Warren (D-Mass.) who's led the charge against his confirmation. She wrote an op-ed last month railing against the revolving door between Wall Street and government regulators, and argued that Weiss isn't even qualified for a job that involves overseeing consumer protection and domestic regulatory functions at Treasury.

The White House has stood by Weiss for the post. White House press secretary Josh Earnest called Weiss "highly qualified" in his Monday briefing, and touted his "deep expertise" in financial markets and economic issues.

Weiss has been meeting privately with senators ahead of his hearing before the Senate Finance Committee. That hearing isn't likely to be held until next year. In the meantime, Democrats have hinted that they are wary about his nomination, but are keeping their cards close to the vest until they've met him in person.

"I hope I get to meet with Antonio before the vote, so I could assess my own view on his credibility and also on what he hopes do with this position," Sen. Kirsten Gillibrand (D-N.Y.) said Friday on MSNBC 's "Morning Joe." "I think Sen. Warren's very clear. She believes that, as the person responsible for how consumers are affected, that his background and his experience doesn't fit the requirements of the job. I'm going to look very seriously at that issue."

"Our number one priority should be getting middle-class incomes moving again and restoring the chance for all Americans to get ahead, and I'll evaluate Mr. Weiss's nomination on that basis once I meet with him," Sen. Jeff Merkley (D-Ore.) said in a statement. "This position is critical for ensuring that the financial system is serving Main Street, and not the other way around."

A White House official said the administration is waiting until January to begin arranging meetings between Weiss and members of the Senate Finance Committee. After first meeting with the chairman and ranking member, Weiss will begin meeting with other members of the committee.

In the meantime, the official said, the administration intends to submit its paperwork on Weiss to the committee next week.

UPDATE: 6:10 p.m. Sen. Al Franken (D-Minn.) said later Wednesday that he, too, will oppose Weiss' nomination.

"This position requires someone who understands how to make our economy work for the middle class and those aspiring to be in the middle class. As such, I will not be supporting Mr. Weiss nomination," Franken said in a statement. "I am troubled by his history working on international corporate mergers for a Bermuda-based investment firm, and his work on so-called inversion deals that allow corporations to change their address and avoid their US tax responsibilities. Wall Streets perspective is already well-represented in the Administration.

UPDATE: 12/11, 2:05 p.m. -- Sen. Tammy Baldwin (D-Wis.) said she will vote against Weiss as well.

"I do not believe Mr. Weiss is the right nominee to push for strong oversight of Wall Street and protect the interests of Main Street as Under Secretary for Domestic Finance," Baldwin said Thursday.

"Based on his record and qualifications as a Wall Street investment banker I dont have confidence that he will work to even the playing field for middle class families and small businesses who need a fair shot to get ahead. With Wall Street lobbyists and Republicans working harder than ever to gut the Dodd-Frank Wall Street reform law, working families need public servants who are committed to remembering the hard lessons of the financial crisis. In addition, Wisconsins small businesses and homebuyers as well as the community banks and credit unions that serve them need a stronger voice in financial policymaking to provide services that work for Main Street, not Wall Street. Regrettably, I do not believe Mr. Weiss is the right choice for this position and I will oppose his nomination."