President Carter's two-month-old partial hiring freeze has not carved large chunks out of the federal bureaucracy, but 1,224 fewer persons are on the payroll now than when the freeze began in early March.

Data to be released today by the government will show a reduction in full-time permanent federal employment from February to the end of March when the government had 2,478,762 civilian workers.

Overall employment of part-time workers increased, mainly because the Internal Revenue Service put thousands of clerical aides on the payroll temporarily to handle tax traffic.

When Carter ordered the 25 per cent hiring cutback, many persons incorrectly expected the payroll to drop by 25 per cent. It did not because the attrition rate always drops during a freeze and because many agencies already had made firm commitments to hire individuals before the freeze. The slight decline, of 1.224, is the net result of Carter's order that agencies could fill only three of every four vacancies.

That partial hiring freeze is still in effect although the White House hoped to end it in mid-April. The plan was to force a trim at the agencies so new, lower personnel ceilings mandated for each by the White House would be met more easily.

The ceilings still have not been approved, mainly because Carter appointees are fighting budget cuts ordered by their boss. Also, new Office of Management and Budget aides, who act as the president's official budget stasher, have not been able to spend enough time with career OMB staffers to agree on agency ceilings.

Insiders expect the freeze to be continue at least another week or two until agencies receive their new ceilings. The over-all cuts are expected to amount to between 20,000 and 30,000 of the 48,000 new federal jobs proposed by President Ford. That would be a reduction of about 2 per cent for the average agency, although some will receive minor or insignificant cuts.

In a government work force of 2.4 million persons, the freeze may seem like a piddling exercise to the average taxpayer. But to the 1,224 persons who normally would have been hired last month, the freeze must seem very solid.