The Carter administration yesterday asked the nation's hospitals to hold their 1979 spending to a 9.7 percent increase, nearly a fourth less than their present inflation rate.

Health, Education and Welfare Secretary Joseph A. Califano Jr. called the voluntary goal -- part of the president's anti-inflation guidelines -- necessary to end the "unnecessary" hospital inflation that has "strained" the economy and "hurt our nation's citizens, especially the elderly."

The administration thus revived, as a voluntary target, a figure close to the 9 percent limit on hospital cost increases it unsuccessfully asked Congress to pass early this year.

Michael Bromberg, executive director of the Federation of American Hospitals, called the 9.7 percnet guideline "totally unrealistic," however, and "based on assumptions we believe are unreasonable." The FAH represents 1,000 investor-owned gospitals and hospital management firms.

Califano pointed out that the administration is asking hsopitals to hold down total spending rather than announced rates, because the agencies that pay most hospital bills -- Blue Cross and the federal gevernment -- pay hospitals only actual costs anyway, not their announced rates.

Unter their new "voluntary effort," the country's 7,000 hospitals have succeeded in holding the rate of increase in their spending to 12.8 percent in the nine months ended Sept. 30. This is more than 3 percentage points under the 15.9 percent rate in the first nine months of 1977.

But Califano said hispital spending again threatens to escalate, since there was a 2 percent rise in hospital room charges last month.

Many hospital officials have also voiced the fear that the nation's rise in general inflation -- and the prices they pay for heat, light, power and supplies -- may force their costs up too.

But John Alexander McMahon, president of the American Hospital Association, has kept saying that he thinks the industry can meet its own goal of reducing its increase in expenditures by another 2 percentage points in 1979.

Califano called the administration request reasonable and achievable for three reasons:

The hospitals' goals call for only a 10.2 percent spending rise next year.

Howpitals should be able to do better, since the president's anti-inflation drive should make the prices they pay for essentials 0.8 percent less than they would have been otherwise.

In 1977 (the year for which there are complete records) almost a third of all hospitals succeeded by "tight management" in operating with less than a 9.7 percent rate of increase in spending.

If hospitals can do as well on the average, he said, the savings will be in the billions -- $69.5 billion in the next six years, including a $26.2 billion saving in federal spending.

Also, he said, the cost of the Medicare hospitalization deductible -- the sum paid by sick older persons on hospitalization -- will have to increase from its present $160 to $232 by 1983 even if the 9.7 percent goal can be met, but will become $276 if it can't be met.

An average 9.7 percent increase for all hospitals was all the administration asked, since some hospitals may have "special problems."

Chlifano also said:

Hospitals that have held their spending increases to 9.7 percent or less this year should cut them by another half a percentage point next year.

Hospitals should spend no more than a $3 billion total on new buildings, additions and equipment costing more than $50,000 next year. This would be two-thirds of the 1976 and 1977 levels, adjusted for 1979 building costs.