Nearly half of the 7,500 employes of the World Bank and the International Monetary Fund walked off the job yesterday to protest a decision initiated by Treasury Secretary James A. Baker III to postpone pay raises.

About 2,000 World Bank employes assembled at noon in the bank courtyard at 18th and H Sts. NW and, after a meeting of the staff association, decided to leave work.

They announced plans to stay off the job when the bank reopens Tuesday, according to bank spokesman Peter Riddleberger.

At the IMF, the sister lending organization of the bank, the majority of the 1,600 employes met Thursday and failed to report for work yesterday, with many calling in sick, according to spokesman Azizali Mohammed.

"Quite a few people have left," said Riddleberger, who added that "I think there are some disciplinary concerns by the senior management" because some workers apparently did not make prior arrangements before taking annual or vacation leave and could be docked pay.

"If there is a big absence again on Tuesday, we will take it more seriously," he said.

Officials estimated that a majority of all employes of the two international financial institutions had left work, although no specific tally was available.

Participating in the walkout were thousands of clerical, secretarial and research staffers, whose salaries average about $20,000 a year, and the professional staff, primarily economists, whose pay is in the $40,000 to $50,000 range, according to fund and bank managers.

The walkout and sickout were triggered by a decision this week of the international executive boards representing the 149 member nations to postpone general wage increases until completion of a long-awaited study comparing salaries with those in comparable workplaces here and in other countries.

Both the bank and the fund have used a pay system since 1979 comparing their employes with those in Japan, Western Europe and the United States for purposes of annual pay raises linked to cost-of-living increases.

But management is currently changing its method of comparison, officials said.

In a recent letter to member nations, Baker recommended postponement of the annual raises. Instead, raises were to be limited to a range of 1.4 percent to 2.9 percent merit raises given to those employes who qualified, according to the decision announced Wednesday.

Employes of the World Bank and IMF have staff associations, but do not have a union that negotiates pay raises. Nor are the associations involved in the current pay study, which will result in changes in the current 25-grade pay system.

Spokesmen for the associations were not available for comment after the walkout.

But management officials said there has been some resentment because of recent job-grading changes in which some categories of jobs were downgraded, and some employe salaries were frozen.

Led by the United States, the governing boards of the two institutions are restructuring the pay system "because we believe there are serious questions" about wages and benefits being excessive, said a Treasury Department spokesman who asked not to be identified.

"They are well paid. They are being denied a raise now, but there is no cutback" planned, he said.