In a corporate election campaign that could end up costing as much as a race for Congress, shareholders of Financial General Bankshares Inc. are being wooed by two rival groups of millionaires.

Only three of the 16 seats on Financial General's board of directors are at stake, but the election probably will determine the future of the $2.2 billion-asset Washington bank holding company.

Election day is April 30, when Financial General's annual shareholders meeting will be held in Richmond.

But like voters casting absentee ballots, most stockholders will indicate their choice by mailing back blue or white cards that are being delivered this week.

The blue cards will cast ballots for all 16 directors nominated by Financial General's management.

The white cards will be counted as votes for three nominees selected by Shiek Kamal Adham, who has emerged as the leader of a group of Middle Eastern investors who have been trying for two years to buy control of Financial General.

The white cards also are votes in favor of a resolution urging Financial General management to end its opposition to the take over by Adham and his group.

Adham's effort to put three members on the board and win shareholder support for the resolution may be his final opportunity to make a bid for Financial General.

The Middle Eastern group is under orders from the Securities and Exchange Commission to drop its takeover attempt if its isn't successful by July 31.

Even if the three insurgent board memebers are elected, the takeover couldn't be completed by July, but success at the annual meeting might persuade the SEC to extend the deadline, Adham has told stockholders.

Operating under the strict SEC rules for corporate elections, both sides make their keynote addresses in proxy statements mailed to shareholders in the last few days.

From now on, any public statements on the matter by either side have to be approved by the SEC, which also monitors election spending.

Adham already has spent $50,000, and the company has spent $100,000, the opening statements say. Financial General reported it expects to spend "at least $250,000," and Adham said he "estimates that his total expenditures relating to the solicitation may be as much as $1 million."

Few races for the U.S. House of Representatives involve more than $1 million in spending, and many U.S. senators and governors have been elected with smaller campaign chests.

The costs of the election will be high because more than half of Financial General's shares are owned by persons who haven't pledged their support to either side.

According to their reports to shareholders, nearly equal blocks of Financial General stock are controlled by Financial General's two top officers and by Adham and his associates.

FG Chairman B. F. Saul II, head of one of Washington's biggest real estate companies, and J. William Middendorf II, the company's president, together claim control of 20.15 percent of the bank's stock, about 1.29 million shares. That includes 277,000 shares in an employe stock ownership plan but controlled by the top executives. Without that stock, Saul and Middendorf have about 16 percent of the vote.

About 18.4 percent of the stock -- 1.18 million shares -- is owned by Adham and Faisal Saud al-Fulaij of Kuwait and Abdullah Darwaish of Abu Dhabi. a

Another 9.5 percent is owned by Eugene B. Casey of Gaithersburg, and 5.3 percent belongs to Dr. Armand Hammer, chairman of Occidental Petroleum Corp.

Hammer and Casey tried previously to bring the two sides together. Both are board members, and each has a second seat on the board held by an associate.

Adham's nominees are Donald Notman, former chairman of National Bank of Washington; Stuart Symington, the former senator from Missouri; and Elwood Quesada, chairman of L'Enfant Plaza Properties. They are nominated at large, not as rivals to any specific members of the 26-person slate of incumbents.