WASHINGTON (Reuters) - Capital One's chief executive Richard Fairbank and other executives will go head-to-head with community groups at a public meeting on Friday convened by regulators to discuss the bank's tie-up with Discover Financial Services ( DFS ).

Unveiled in February, the $35 billion deal will create the biggest U.S. credit card issuer by balances, the sixth largest bank by assets, and will give Capital One control of Discover's card payment network, the fourth major payment network operator.

Virginia-based Capital One and other proponents say the deal could boost card payments competition but opponents fear it will reduce services, increase costs for Americans and threaten financial stability by creating another too-big-to-fail bank.

The Federal Reserve and Office of the Comptroller of the Currency (OCC), which are under political pressure to be tough on mergers, are holding Friday's meeting in a rare move reserved for the most contentious merger reviews.

The meeting, which is slated to run all day, offers opponents a platform to ramp up that pressure.

Top congressional Democrat Maxine Waters, the National Community Reinvestment Coalition (NCRC), a powerful coalition of non-profits, and advocacy groups Americans for Financial Reform (AFR) and Public Citizen are among those that will speak against the merger, according to a schedule posted by the Fed.

"Approving this merger would exacerbate the problems of financial stability, safety, and soundness," Bartlett Naylor, policy advocate for Public Citizen, said in a statement.

Reuters reported on Wednesday that Capital One had committed $265 billion over five years to lending, philanthropy and investment if the takeover goes through, as it tries to appease critics and win over regulators.

That community benefits plan, more than twice as big as any to date, according to data from the NCRC which negotiated all previous plans, will also be under scrutiny on Friday.

Speaking to Reuters this week, Andres Navarrete, Capital One's head of external affairs, said he believed the regulators care deeply about the plan, although the NCRC and AFR have questioned whether it will do enough to help communities.

The Fed and OCC assess the deal's impact on the convenience and needs of affected communities, as well as financial stability, and competition, among other issues. The Justice Department also provides its view on the antitrust implications.

That process could take several more months, said regulatory experts.

Beyond Capital One and Discover executives, several Virginia state lawmakers and advocacy groups are expected to speak in favor of the deal, according to the agenda. Vocal support from civil rights or community groups could be helpful for Capital One.

"Community support ... positively affects the regulators' views of the transaction," said Chip MacDonald, an M&A lawyer and managing director at MacDonald Partners.

"Where antitrust concerns are present, this could also be a basis for a bank regulator finding that the public benefits of the merger outweigh the competitive concerns."