The nursing shortage of the 1960s and 1970s is largely over, a National Academy of Sciences investigating committee reported yesterday.

One reason, according to the American Nurses Association, is the economy. Fewer nurses are needed because fewer people can afford to get medical care and more former nurses are going back to work to supply it.

Serious shortages of nurses still exist for the aged, for inner-city dwellers and for some kinds of patients, the academy said, but the federal government should now use its funds to help meet those needs, not increase the general supply of nurses.

The committee also called the prevalent idea that nurses have been deserting their profession in droves a "myth." It said 76 percent of all graduate registered nurses are active, about the same as the rate for all college-educated women and up from 60 percent in 1970.

The investigating group predicted that the general nurse supply will remain "in reasonable balance" throughout the 1980s.

But it conceded that shortages also may remain in some geographic areas. Some Washington hospitals are still offering premium pay for nurses to work weekends, as one example.

But in California last month Stanford University Hospital announced, "We are not doing any hiring," and added, "Two years ago the turnover rate was 37 percent, which was very low nationally. Now it is less than 1 percent."

The 25-member study group was named by the science academy's Institute of Medicine at Congress' request two years ago. It was headed by Arthur E. Hess, former deputy Social Security commissioner.

The nursing shortage of the 1960s and 1970s was caused, said the committee, not by nurses' deserting the field but by an "explosive demand" caused by a sudden flood of new medical technologies: intensive care, cardiac care, kidney dialysis, transplants and many more, all requiring more nurses and more medical personnel of all kinds. In response to that shortage, truly "extreme," the committee said, Congress in 1964 enacted a Nurse Training Act to aid nursing schools and nursing students. The committee urged that the act be reauthorized, with new aims.

It urged continued scholarships and loans for nursing students who, Hess said, "usually come from families of modest means" and depend on such help, and graduate-level programs to train the kinds of nurses needed to meet remaining gaps.

The group urged the government to restructure Medicare-Medicaid payments to improve and encourage long-term care for the country's growing ranks of aged and chronically ill, and to move toward "24-hour R.N. coverage" at nursing homes.

The group also urged better pay for nurses, whose average pay in 1981 was $331 a week.