Citing economic uncertainty, employers in metropolitan Washington say they will hire fewer workers in the last three months of the year than during the final quarter of 1980, a national survey shows.

The survey, conducted by Manpower Inc. of Milwaukee, found that employers here generally share the concerns of their counterparts nationwide, who indicated that hiring activity will remain sluggish through the end of the year.

"In general, the Washington area mirrors what's going on on a national basis," said Mitchell S. Fromstein, president of Manpower, a temporary-help supplier.

"I think there is a pall of uncertainty that hangs over the business community today," Fromstein said in a recent interview. "When you look at the general business community, everybody's got a wait-and-see attitude. And when you have that type of attitude, there is a tendency not to hire."

Fromstein said high interest rates are having a "paralyzing effect" on the economy, both in highly industrialized regions and in services-oriented areas such as metropolitan Washington.

Manpower's survey of employers here found 23 percent of those polled plan to add to their staffs in this year's final quarter, down slightly from 30 percent a year ago. At the same time, 6 percent said they will reduce their work forces, while another 67 percent plan no changes.

In the District, 18 percent expect to hire more workers by the end of December, compared with 38 percent a year ago. At least 6 percent said they plan layoffs by then.

Hiring expectations are more optimistic in suburban Maryland, but cutbacks in Northern Virginia probably will be sharper than they were in the final quarter of 1980.

Manpower's survey of employers in Prince George's and Montgomery counties found that 30 percent plan to expand their staffs in the fourth quarter, compared to 26 percent in the comparable period a year ago. Only 4 percent contemplate staff reductions, and 66 percent plan no changes.

In a similar survey last year, 30 percent of the respondents in Northern Virginia said they planned to increase their staffs. In the latest poll, however, only 7 percent said they will add employes.

In Northern Virginia, 60 percent of employers said they will maintain their work forces at present levels, and 3 percent said they are uncertain.

Although the usual seasonal increase in hiring is expected to begin soon, additions in the wholesale-retail sector won't be as large as in previous years, Manpower's survey indicated.

"There isn't that characteristic pickup you normally see this time of year," Fromstein said.

Although he would not identify executives who participated in the survey of local businesses, Fromstein said typical comments were: "I can't afford to build inventory with interest rates where they are," and "activity will resume when interest rates come down."

Manpower calls itself the world's largest temporary-service firm. Its employment outlook surveys are conducted quarterly, and findings are based on interviews with about 10,000 public and private employers in more than 300 cities.