The number of lawyers in America is expected to reach 1 million by the next decade, confronting the legal profession with new problems of declining income, underemployment and even unemployment, experts told lawyers here today at the annual convention of the American Bar Association.

One law professor said that as a result of the field becoming crowded he has already seen efforts by lawyers to increase their work load, sometimes to the detriment of the general public. Professor Ted Finman of the University of Wisconsin Law School cited attempts through advertising to persuade consumers that they need lawyers, an increase in "dubious" legal claims by lawyers and greater attempts to monopolize law-related work by keeping non-lawyers from competing.

"We may be reaching a point where the numbers are more than we can handle," said Gary C. Huckaby, an Alabama lawyer and former chairman of an ABA committee on the delivery of legal services.

"I think we ought to warn students that there might be some potential danger," Huckaby said.

The comments of Huckaby and Finman came during a panel discussion on the future of the legal profession and reflected one of the major preoccupations of this year's convention, the lawyer glut. The trend is particularly striking in view of the traditional assumption that going to law school was a sure route to financial and professional success.

Statistics released here today by the American Bar Foundation show that the number of lawyers has increased from about 250,000 in 1960 to about 622,000 in 1983.

By 1987, said Barbara A. Curran, associate executive director of the foundation, "There will be three-quarters of a million licensed lawyers . . . . Assuming that the level of law school admissions neither rises or drops substantially in the next 10 years," she said, "we may expect that the legal profession will reach the 1 million mark by the mid-1990s."

She said that growth rate substantially exceeds the population's growth rate. In 1960, she said, there was one lawyer for every 632 persons. Now there is one lawyer for every 375. (The District of Columbia has the highest ratio in the nation: one lawyer in private practice for every 65 residents. Many of these lawyers, however, do not compete in a local market but in a national market.)

"What this means in basic economic terms," Finman said, is a decline in lawyer income. "As a profession, we have responded to this situation by seeking to increase consumption" of legal services, he added.

He said that lawyers are increasingly turning to advertising to convince people "who previously saw no need to go to a lawyer" to go to one.

Huckaby said he sees more and more tactics that tend to increase lawyers' work and income, whether or not money is the motive. "It used to be that settlement of a dispute was the first road a lawyer would take," he said. "Now settlement is the last road we take."

Huckaby also noted a tendency for several lawyers representing the same client to appear in court at the same time on the same matter, boosting client bills. "They travel in packs," he said, adding that sometimes the sole function is for "one to pat the other on the back after he sits down."

"A large portion of good lawyers are underemployed or unable to find work," Huckaby said. However, he said that limiting law school admissions is not the answer.

"If there are too many lawyers," he said, "the market will take care of this. It might create some economic hardship, but the marketplace must govern in the best of American traditions."