CINCINNATI, FEB. 15 -- Campeau Corp. has sweetened its bid for Federated Department Stores Inc. to $65 a share, or about $5.75 billion in cash, as Federated's board prepared to review offers for the company, Federated said today.

Federated said its board may take action on bids for the company at a meeting on Tuesday.

The company has twice spurned Campeau. Federated rejected Campeau's initial $47-per-share, $4.2-billion takeover offer as inadequate and turned down an improved $61-per-share, $5.4 billion bid because it was not convinced Campeau had the necessary financing.

Federated said in a written statement that it has been negotiating with numerous parties, including Campeau. Company officials said that the negotiations involve the possible restructuring of Federated, a Cincinnati-based retailer that operates about 650 stores in 36 states and had sales exceeding $11 billion in 1987.

"The purpose of these negotiations is to be able to present to the company's board of directors ... several alternatives for the board's consideration," Federated said today.

"Each of the parties has been urged to make its best proposal, because the board may take definitive action at that time," the company added.

Other than Campeau, Federated did not identify any other parties involved in the negotiations, but analysts have said that they suspect New York investment banker Kohlberg Kravis Roberts & Co. to be one of them.

In a Feb. 5 Securities and Exchange Commission filing, Federated revealed it was considering alternatives, including selling assets, restructuring or an outright sale of the company.

Campeau's latest offer came in a letter over the weekend.

Federated officials quoted the Campeau letter as saying: "We understand that a meeting of the board of directors is scheduled for Tuesday, Feb. 16, and this is to confirm that at that time, Campeau Corp. will submit an all-cash offer in excess of $65 per share."

Federated had no comment on the possibility that the bid could be increased.

New York analyst Monroe Greenstein of Bear, Stearns & Co. said $65 was in the area of a fair price but he suspected Federated would attempt to resist.

"I think they're going to weigh all alternatives, but I still believe that if they can find a way to remain independent, they will," Greenstein said.

"They talk about alternatives, including a restructuring or sale of securities. You can sell securities and still stay independent," Greenstein added.

Greenstein said that Campeau perhaps was pushing up the cost of remaining independent and "Federated could wind up with a lot of angry shareholders if they don't come up with something that's worth to the shareholders at least what Campeau is offering."

Campeau, a Toronto-based development company, bought Allied Stores Corp. in December of 1986. Campeau sold several divisions of Allied, including Washington-based Garfinckel's, but retained retailing chains, including Ann Taylor, Brooks Brothers and Jordan Marsh.

Ohio politicians are worried that Campeau will buy Federated, sell major portions of the company and fire or lay off large numbers of its employees.

Sen. Howard Metzenbaum (D-Ohio), who is the chairman of the Senate Judiciary Committee's antitrust subcommittee, said last week that he is concerned that a Campeau purchase of Federated could reduce competition among retailers in New York City, Boston and Miami, where Allied and Federated both own stores.

Federated's holdings include the New York-based chains of Bloomingdale's and Abraham and Straus, Filene's of Boston, Burdines of Miami, Rich's in Atlanta, Bullock's and Bullocks Wilshire in Los Angeles, I. Magnin in San Francisco and Lazarus in Cincinnati.

Federated spokesman Jim Sluzewski declined to say whether he expects an announcement to be forthcoming from Tuesday's meeting.

"Among the factors which the Federated board will consider in connection with any proposed sale or restructuring transaction are the risks inherent in any such transaction, the financial capability of the purchaser, and the extent to which any purchaser may have taken action to discourage others from submitting proposals to the company," Federated commented in today's statement.

"There can be no assurance that any definitive transaction will take place," the Federated statement added.

Company officials declined to elaborate.

In a separate development, Campeau has obtained a restraining order against enforcement of a recently enacted Ohio law that makes takeovers by foreign companies more cumbersome.