The average income of physicians increased about $11,000 to more than $155,000 in 1989, according to a study by the American Medical Association.

The 7.7 percent increase outstripped the rate of inflation, as measured by the consumer price index, which increased 4.6 percent in 1989.The president-elect of the AMA, the nation's largest organization of doctors, said Friday he could see public concern about the increase but he didn't think doctors as a group "are overpaid or underpaid."

"I would expect the average person's reaction to be surprise, but when you think about the number of hours a doctor works in a week, and some of the training, the intensity of some of the work in some of the specialties, I think it's understandable," said Dr. John J. Ring.

Ring, a family physician in suburban Mundelein, noted that the increase in 1989, the last year in which the figures were available, was smaller than most years since 1981.

Family physicians earned the least, an average of $95,900 in 1989 compared with $94,600 in 1988. Surgeons earned the most among specialists, a 1989 average of $220,500 compared with $207,500 in 1988.

Charles Inlander, president of the People's Medical Society, a consumer interest group in suburban Philadelphia, called the figures "another example of how doctors gouge the public. It is immoral for doctors to have this kind of income when 15 percent of the population has no health-care insurance," he said.

But in addition to long years of education and long hours after beginning practice, there is also the cost of malpractice insurance and difficulties getting paid through the Medicare system, one physician said. Primary care doctors often lose their Medicare payments to specialists they have referred their patients to, he said.

Insurers have long paid high fees for technical procedures and operations and much less for the hours that primary care doctors spend figuring out which treatments their patients need. But beginning in 1992, Medicare will reimburse doctors more for their time managing and evaluating patients and less for technical services and operations.