Rep. Maxine Waters vowed Monday to fight allegations that she violated House rules as the ethics committee announced that the California Democrat will face a rare public trial.

The Committee on Standards of Official Conduct confirmed Monday that an investigative subcommittee found substantial reason to believe Waters violated House rules. An adjudicatory subcommittee will be convened at an unspecified date to review the charges against Waters and determine her guilt or innocence.

The panel did not detail the charges against Waters, but she has been the subject of an investigation since October 2009 focused on her relationship with the National Bankers Association and OneUnited Bank, the latter of which received $12 million in federal bailout funds.

“I have not violated any House rules,” Waters said in a statement Monday. “Therefore, I simply will not be forced to admit to something I did not do and instead have chosen to respond to charges made by the House Committee on Standards of Official Conduct in a public hearing.”

The California lawmaker also dismissed an Office of Congressional Ethics report released Monday, which reviewed the same allegations, characterizing questions over her actions as “frivolous and unfounded.”

The OCE, which reviews potential rules violations and recommends probes to the ethics committee, found that Waters likely violated House rules on conflict of interest when she arranged a September 2008 meeting between the National Bankers Association and the Treasury Department.

“The rules and precedent cited above clearly enunciate a standard that restricts Members from advocating for a matter in which they have a personal financial interest,” the OCE stated in its report. “Therefore, if Representative Waters advocated for OneUnited while her husband maintained a significant investment in the bank, then she may have violated House Rule 23 and House standards regarding conflicts of interest.”

Waters’ husband, Sidney Williams, served on OneUnited Bank’s board until April 2008 and owned $100,000 to $250,000 in the company’s stock at the end of 2008, according to Waters’ annual financial disclosure.

According to the OCE’s report, Waters recognized the conflict of interest, expressing her concerns in a conversation with another lawmaker.

“Representative Waters told Representative A that she was in a predicament because her husband had been involved in the bank, but ‘OneUnited people’ were coming to her for help. According to Representative A, she knew she should say no, but it bothered her,” the report states.

“Representative A” is identified in documents as the chairman of the Financial Services Committee, a position held by Rep. Barney Frank (D-Mass.).

According to the OCE report, Waters agreed to orchestrate a meeting between the NBA, which represents minority-owned banks, and the Treasury Department in September 2008.

But the meeting allegedly focused “on a single bank — OneUnited,” the report states, and two of three NBA officers in attendance also held posts with OneUnited. The bank’s president also attended.

“OneUnited was represented at the meeting as illustrative of what could happen to the sector if the Federal government did not assist them. OneUnited was the only bank independently represented at the meeting,” the report noted.

Waters, who did not attend the meeting, rejected allegations that the event was called to focus on OneUnited.

“The OCE focuses on concerns expressed during the meeting between NBA and Treasury on behalf of a single bank. However, NBA’s follow up letter, dated September 10, 2008 … to Treasury reiterates the organization’s concerns about the fiscal health of its members generally,” she said.

Waters becomes the second lawmaker to move toward an ethics trial in the 111th Congress, only days after the Committee on Standards of Official Conduct initiated proceedings in an unrelated investigation of Rep. Charlie Rangel (D-N.Y.).

The adjudicatory subcommittee, composed of four Democratic and four Republican lawmakers, will determine whether Waters violated any rules. Both Waters and ethics committee counsel could present evidence and call witnesses to testify during the trial.

If the adjudicatory panel finds Waters culpable, the ethics committee will then convene to determine a punishment. The full House could also be called on to vote on sanctions, if the punishment rose to the level of a reprimand, censure or expulsion from the chamber.