Federal bank regulators yesterday opposed congressional efforts to give small savers the same return on their money as large investors.

Testifying before the Senate Banking Committee, Robert H. McKinney, chairman of the Federal Home Loan Bank Board, said adoption of Senate proposals to give the $1,000 depositor the same interest rate as the $10,000 saver would be too costly for savings and loan associations.

The bank board, along with other federal regulatory agencies including the Federal Reserve Board, has proposed new types of small savings certificates with improved interest rates. But the rates would still be less than those paid large depositors.

Sen. William Proxmire (D-Wis.) suggested that the volume of money market certificates instead be limited in the manner of bond offerings, and that rates be uniform no matter the size of the individual purchase.

McKinney replied that whereas nearly half of maney poured into $10,000 money market certificates last year was "new" money, most of the funds for small money market certificates would be "old" money from persons upgrading their savings accounts. This in turn would mean less new revenue available for mortgage lending.

Consumer advocates vowed yesterday that if the regulators would not grant small savers parity, they would take steps to end what Robert Gnaizda, a San Francisco lawyer representing the Gray Panthers, termed a "$17.5 billion annual unwitting subsidy of the wealthy by the small depositor."

He singled out the Bank of America which, he said, averaged $14.4 billion in low interest passbook deposits last year. The difference between the interest rate paid and the market rate (5 percent versus about 9.5 percent) was $504 million. That helped to explain, in part, the bank's 30 percent increase in profits last year, he said.

Gnaizda told how the Panthers had already begun to pool their funds to take advantage of maximum rates. On Mar. 28 Security National Bank of California began forming pools of $1,000 or more participants. Last week the bank took in $1 million from 350 depositors. The national Association of Retired Persons also said it was investigating the possibility of establishing its own money market fund.

Though there is no prohibition against pooling in federal regulations. Federal Reserve governor Charles Partee said yesterday it violated the "spirit" of the board's rules. He declined to say whether the Fed would stop Security National from pooling as the bank board stopped another recent attempt by a Cleveland S&L. Yesterday McKinney admitted the action had been "a little heavy handed," adding, "I have some reservations about enforcing (anti-pooling) rules like that."

There was general agreement among the regulators that Regulation Q, which sets ceilings on savings accounts, should be phased out. Besides discriminating against small savers, Comptroller of the Currency John G. Heimann testified the ceilings have caused disintermediation with detrimental effects on housing funds. Heimann said he expected the outflow of funds from savings and loan associations to other types of investments-particularly money market funds which pay high market rates on deposits as low as $1,000-to increase.

However, there was disagreement over the timing of the phase-out. Heimann and Proxmire would like it to begin concurrently with a phasing in of new investment powers for thrifts. McKinney argued that the new investment powers, in particular the ability to make wariable rate mortgages nationwide, should be instituted before interest rate ceilings are removed. VBMs allow the interest rate to rise (or fall) according to economic conditions and therefore provide S&Ls with more funds to pay higher interest rates to depositors. CAPTION: Picture, SEN. WILLIAM PROXMIRE. . . proposes equal savings rates