The incoming president of the American Bar Association warned law students yesterday that they face an increasingly tough time finding jobs as lawyers.

"The realities of lawyering" may compel them to use their legal education in other professions, said S. Shepherd Tate.

"Clearly anyone looking to the law as an automatic ticket to affluence is likely to be doomed to disappointment," said the Memptis attorney who takes over as ABA president this week.

His speech to the law student division at the ABA's 100th annual meeting here was the first time a top official of the organized bar has faced up publicly to the new economic facts of life facing the legal profession.

A relative handful of the nation's 462,000 lawyers, especially partners in top New York and Washington firms, have six-figure incomes. A survey of firms by Price Waterhouse accountants showed that top partners in the largest New York firms have median incomes of $161,000 a year, and some Washington partners are reported to make even more.

However, the median income last year of ABA members was $30,000 - $2,000 less than 1976.

Moreover, with twice as many law students graduating each year as 15 years ago, competition for the available legal jobs is growing. The Labor Department estimated that this year's 30,000 law school graduates will be fighting for only 21,000 jobs in the legal profession.

As an example of unemployment, Tate cited a survey by the California Young Lawyers Association. Of 22,500 lawyers admitted to practice there since 1972, more than one in five are having grave problems finding jobs as attorneys.

Recognizing these problems, the ABA Young Lawyers Division urged the organized bar to insist that all ABA-accredited law schools run placement programs to help new graduates.

"The Young Lawyers Division considers to be one of the most important concerns for the organized bar today, and one that will not go away," said its president, William H. Neukom of Seattle.

In his speech, Tate said, "Some older lawyers have expressed concern over what they see as the economic threat of these legions of young lawyers." They have suggested that the ABA "limit law school enrollments and thereby restrict the number of new lawyers."

Tate opposed this, saying it appeared to violate antitrust laws and would be unfair to young lawyers who want to join the profession.

Instead, he said, "We have an affirmative obligation to warn young people that a juris doctor degree is not a gurantee of fortune and financial independence."

He pointed to new fields of law - consumer, environmental malpractice and liability, public interest and regulatory - as "growing areas of legal activity (that) after many opportunities for new lawyers."

He also advised young lawyers to seek jobs in business and industry that allow them to use their legal training. Tate quoted an ABA survey that found twice as many lawyers working in non-legal departments of companies as in legal departments.

Tate acknowledged a report released last week by the National Association of Law Placement that said 94 percent of last year's law school graduates have found "law related jobs."

Nonetheless, he said, "there are indications that unemployment and underemployment among lawyers is a serious problems."

Experts here said the 94 percent figure may be an overstatement, since it relied on information from only two-thirds of last year's graduates. Those not included in the survey came from schools whose graduates have the hardest time finding jobs as attorneys - those not accredited by the ABA and those that are ranked lowest by prospective employers.

Recruiters for the top law firms which pay the highest salaries - as much as $23,000 to start at the biggest Wall Street firms - have said they are looking only for the top 10 to 20 percent of the graduates in the very few highest-ranked law schools. For the rest of the graduates, Tate said, "there has been a shift from a sellers' market to a buyers' market for the services of new lawyers."