Albert Shanker, president of the American Federation of Teachers, proposed yesterday that a rigorous national exam be developed for licensing new teachers and said his union eventually would refuse to admit anyone who failed it.

In a speech to the National Press Club, Shanker said the examination should be comparable to exams required to practice medicine or law. He predicted it would raise teachers' status and salaries.

"Unless such a standard is adopted, we believe the benefits of the recent education reforms will soon go down the drain," Shanker said. "It is important that our teachers know more than the children they are teaching -- much more . . . and that they have the status of professionals."

Since 1977, about 20 states, including Virginia, have begun to require teachers to pass licensing exams. But Shanker said most of these tests "would be considered a joke by any other profession," because they are "minimum competency exams."

Elsewhere, including Maryland and the District of Columbia, teachers are licensed on the basis of whether they passed certain courses at colleges with state-approved education programs. Montgomery and Prince George's counties also give short basic skills tests to applicants for teaching jobs.

Shanker said Florida requires elementary teachers to pass a test in sixth-grade-level mathematics. "That's equivalent to licensing a doctor on the basis of elementary biology," he said.

Shanker suggested that within six months leaders of education organizations, college presidents and perhaps leaders in other professions should join in establishing a "Board of Professional Education" to develop standards for the proposed exams and to administer them. He said the tests should cover the subjects that prospective teachers intend to teach, as well as their knowledge of teaching methods and their ability to make "instructional decisions."

He said there should be a national passing score, in contrast to the current situation in which each state sets its own passing grade on the portions of the National Teachers Examination that it uses. That exam, which Shanker criticized as too easy, is produced by the Educational Testing Service.

In a statement released after Shanker's speech, Mary H. Futrell, president of the rival National Education Association, said her union believes in "the basic right of the states to determine who is qualified to teach." The NEA has long opposed requiring teachers to pass a licensing exam and contended that a written test cannot measure teaching ability.

Yesterday Futrell said, "The score of a test might be one aspect of a comprehensive teacher-evaluation program."

David Imig, executive director of the American Association of Colleges for Teacher Education, said he "welcomes" Shanker's proposal.

Shanker said that within a few years there will be "a substantial teacher shortage," adding that unless strong national licensing standards are established "the states will ignore the standards they have" to get more "warm bodies" into the classroom. "In the midst of all the talk about excellence and quality," he said, "we're actually about to lower standards."