The Federal Reserve Board announced yesterday it had approved a Los Angeles bank holding company's application to set up a trading system for options on U.S. government bonds.

The Fed's permission to Security Pacific Corp. to provide services for the trading of options on U.S. Treasury securities came despite loud opposition from three Chicago exchanges that offer similar services.

It marks another step for banking companies in their attempt to move beyond the world of loans and checking accounts into more sophisticated -- and profitable -- financial services.

The victory may be short-lived, however, as Congress has passed a bill forbidding bank holding companies from engaging in such options deals before March 1, 1988.

The Federal Reserve's Board of Governors noted that and said it may have to adjust its ruling depending on whether President Reagan signs the bill.

The new system would create a slightly different way of trading options on the billions of dollars' worth of bills, notes and bonds that the debt-ridden United States government sells in order to keep operating.

People who buy those securities often sell them later. Some people who want to buy such bonds in the future will take out an option, agreeing to buy a certain number of Treasury bills at a set price within a certain time period.

Security Pacific, the nation's seventh-largest bank company with $64 billion in assets, would enter the options business through two subsidiaries, Security Pacific Options Trading Corp. and Security Pacific Options Services Corp.

The first subsidiary would act as a so-called "blind broker," providing the automated network making options trading possible.

The other company would act as a clearing agent, comparing offers, matching potential deals and settling them.

These services already are provided by the Chicago Board of Trade, the Chicago Mercantile Exchange and the Chicago Board Options Exchange.

But those groups have set specific terms on each kind of option contract available, the Federal Reserve said. The terms of the options to be traded on the Security Pacific network will be flexible and subject to negotiation.

All six Fed governors approved the Security Pacific request except for Fed Chairman Paul A. Volcker, who was absent