Hiring activity across the nation should remain steady in the first three months of 1989, a survey by Manpower Inc. showed.

Manpower, a temporary employment services company, surveyed 14,000 companies nationwide and found that 22 percent of respondents said they intend to add to their work force in the first quarter of next year while 11 percent plan to reduce employment.Those figures compare with 21 percent who said they would increase their work force in the first quarter of 1988, while 12 percent of respondents then said they would decrease activity.

"We were a bit surprised at the hiring strength indicated by these new figures," Manpower President Mitchell S. Fromstein said in a statement.

"After a year in which 3 million new jobs were added to the U.S. work force, we expected to see a slowing down of job formation, but apparently the demand for new workers will continue unabated, at least through the first quarter."

The survey showed hiring demand appeared strong in all major sectors except construction and wholesale-retail trade, where declines are expected in the first quarter. However, the seasonal drop in wholesale-retail trade should be less than usual, Fromstein said.

Fromstein said the figures for all regions of the nation were positive. Hiring will be strong in the South and West while hiring plans are more positive in the Midwest than in any recent first quarter, bringing them to a level that equals those in the Northeast.

Manpower conducts the Employment Outlook Survey on a quarterly basis. It is based on telephone interviews with nearly 14,000 public and private employers in 423 cities.