The number of blacks and other minority groups members in high-paying federal jobs is continuing to increase rapidly, the U.S. Civil Service Commission reported yesterday, even though over all federal employment has declined.

At the top of the federal service ladder, the number of minority employees holding jobs that pay over $20,000 a year (in grades GS 12 and above) increased by 15 per cent between May, 1975 and May, 1976, the commission said.

Since 1973, the number of minorities in these jobs has climbed by 39 per cent, the commission said, while the number of whites in them has risen by 6 per cent.

Minorities now account for 7.1 per cent of the government's top civil servants (in GS 12 and above), compared to 5.5 per cent in 1973 and 2.8 per cent in 1970.

A spokesman for the Civil Service Commission said the new figures show that the government is making "steady progress" in increasing the number of black and other minority employees in good jobs and that affirmative action programs to recruit and upgrade them "are working."

He noted that some critics have charged that the change at the top levels hasn't been fast enough. On the other hand, he said, some white employees have complained that they are now victims of "reverse discrimination."

The number of government jobs held by women is covered in separate reports which have shown sizeable increases in the number of women in top civil service ranks over the past few years.

According to the new report on minorities, the total number of federal civilian employees fell last year by 13.296 to 2,424, 772.

Even so, it said, the number of minority group workers increased by 2,801 to 21.1 per cent of the federal work-force.

Blacks accounted for 15.9 per cent of all federal employees. In addition, 3.4 per cent were Spanish-surnamed, and about 1.9 per cent were American Indian or Oriental.

According to the Census Bureau, non-whites and persons of Spanish origin now comprise about 17 per cent of nations working-age population (16 to 64), with blacks making up 10.5 per cent of the total.

Among blacks, there was a 14 per cent increase last year in the number holding top federal white-collar jobs, but a slight decline in those in blue collar jobs, the Postal Service, and in the very lowest ranks of white-collar civil service.

Nevertheless, blacks still comprised 20.1 per cent of the workers in GS 1 to 4 (earning from $5,800 to $10,800 a year) compared to just 3.4 per cent of those in the super-grades 16 to 18, earning from $39,629 to $54,410. In 1973, though, blacks made up just 2.5 per cent of the super-graders.