Despite the fact that there is a freeze on federal pay raises, there may be modest salary boosts in store next October for some government engineers, scientists and secretaries whose agencies are having trouble competing with private industry in attracting workers.

The raises may go to some of the 30,000 "special rate" workers already paid from 6 to 20 percent more than their grade level requires.

The Office of Personnel Management, which controls pay scales for the employes, has asked federal administrators around the country to check private industry pay scales in their areas. OPM wants to know which agencies are having trouble keeping employes with specialized skills because the pay is too low.

The government pays many of its scientists, engineers and medical personnel in hard-to-fill jobs higher salaries than other workers at the same grade level.

Because the government has difficulty competing in its clerical recruitment with the high-tech industries in Los Angeles and Boston, the government also pays some clerical employes in those cities more than federal clericals elsewhere in the country.

After it studies agency special pay reports, OPM decides annually which group of special-rate employes are due raises. The government doesn't try to match industry dollar for dollar, especially in the engineering fields.

It grants raises to special-rate employes only when agencies prove that they can't compete with industry pay.

Many federal agencies, especially those employing engineers, have complained that they are having trouble getting top-notch college graduates. If they can convince OPM that pay is the primary factor, the personnel management office will order selective raises this fall. Job Mart

The Defense Mapping Agency has openings at Fort Belvoir for a Grade 12 systems accountant; two vacancies for GM (merit pay) 13 systems accountants and one opening for a GM 14 supervisory systems accountant. Call Robin T. Mazyck at 295-0729.

Department of Education wants two supervisory attorneys, GM 15. Call Marilyn McCarroll at 732-2607. Meetings

Health writer Jean Adams will speak at the meeting at 1 p.m. today of the Annandale chapter of the National Association of Retired Federal Employees. The meeting is at the Annandale Fire Station.

The Training Officers Conference meets April 8 at the Fort McNair Officers Club. For reservations call Richard A. Burdick at 275-2882. Health Insurance Refunds

Federal workers and retirees who had Blue Cross-Blue Shield health insurance last year should be getting premium refund checks shortly. Two weeks ago the company mailed 1.4 million applications for refunds to 1985 subscribers. As of last Friday more than 800,000 of the application forms had been signed and returned to the company.

Blue Cross-Blue Shield said it will be mailing about 500,000 refund checks this week.

The National Association of Letter Carriers has sent refunds to the nearly 200,000 persons who were 1985 subscribers to its health plan. Other companies offering refunds are Aetna, Government Employees Hospital Association, Government Employees Benefit Association, the Foreign Service health plan and the American Federation of Government Employees health plan. There has been no word from them as to when refunds will be mailed.