Fine-tuning federal pay on a city-by-city basis will be expensive, according to new estimates from the Congressional Budget Office. Locality pay is just one of three components in a new federal pay system that:

Provides for a nationwide federal pay raise each year. It is based on national changes in private pay. The first raise will be in January 1992, and it will be 4.2 percent. Last month, workers got a 4.1 percent raise, the last to be based on the old system of determining raises.

Allows the president to give special raises of up to 8 percent to federal workers in high-cost cities. Those raises now are in effect for employees in New York City, Los Angeles and San Francisco. Office of Personnel Management Director Constance B. Newman said yesterday it is unlikely the Washington area will get special raises this year, despite pressure from local politicians and the area's 360,000 federal workers.

Attempts to bring federal salaries in line with local industry on an area-by-area basis. It begins in 1994. The budget office estimates the first-year cost will be $1.5 billion.

By 2002, only 11 years away, the hometown pay catch-up system will cost an additional $10 billion, according to the congressional agency.

The budget office's estimates could be on the conservative side. In the past it has put the government-industry pay gap at 20 percent. The Bureau of Labor Statistics, whose pay data will determine the city-by-city raises, has indicated a pay gap of nearly 30 percent.

Gulf Blood Donors

Employees at the Labor Department roll up their sleeves today for a special blood drive at the Frances Perkins Building. The Red Cross will send the blood to the Persian Gulf to help wounded military personnel. To initiate the program, Secretary-designate Lynn Martin, Acting Secretary Roderick DeArment, Assistant Secretary Thomas Komarek and Michael A. Urquhart, president of the American Federation of Government Employees, have promised to be among the first in line.

Cost-of-Living Adjustments

Injured employees and beneficiaries under the Federal Employees Compensation Act will be getting a 6.1 percent cost-of-living adjustment March 1. Retired federal workers, military retirees and people under Social Security who are under a different adjustment cycle received a 5.4 percent adjustment last month.

Honoraria Ban

House Judiciary Committee hearings start Thursday on bills to allow federal workers to write or speak off-duty for pay. Thanks to a glitch in the congressional ethics law, workers who receive what is considered honoraria can be fined up to $10,000.

Reps. Constance A. Morella (R-Md.) and Barney Frank (D-Mass.) are sponsoring a bill that would allow federal employees to moonlight for money.

Hundreds of workers in the Washington area who sometimes write articles, review books or give lectures are affected by the ban. The National Treasury Employees Union and American Federation of Government Employees have gone to court attempting to block the law until Congress decides whether to rewrite it.