The National Education Association, in a sharp break from a decades-old tradition, voted yesterday to support dismissal proceedings against incompetent teachers as well as competency exams for all new teachers trying to enter the field.

The two votes marked a shift to a more moderate stand for the traditionally liberal NEA, the largest teachers' organization and one of the largest unions in the nation. The shift was largely the work of NEA President Mary Hatwood Futrell, who has been pushing her union to get behind the reform bandwagon to avoid being run over by it.

The vote on competency exams for new teachers became a key test of Futrell's leadership of the 1.7 million-member union. The vote was expressed by overwhelming shouts of "Aye!" from the 8,000 delegates.

Futrell first announced her intention of pushing for the teacher-testing vote in an interview with The Washington Post in May, when she said, "the times have dictated that we place more emphasis on the professional issues."

When the story appeared, Futrell said, she sent copies to NEA affiliates across the country to test the reaction -- and to her surprise found that many of her members had been thinking the same thing.

The resolution on teacher testing states that the NEA "advocates rigorous standards for entry into the teaching profession." Those standards include above-average grades in teacher training school, a student-teaching stint, and passing a test that is "valid and unbiased" before being allowed into the ranks of teachers.

Still, the NEA reiterated its longstanding opposition to tests of already-employed teachers, an idea that has become increasingly popular among parents and state legislatures. Arkansas has tested its 28,000 teachers, and Texas and Georgia have passed laws requiring similar tests. Ten percent of those tested in Arkansas failed the first round of tests.

The NEA has opposed standardized tests on the ground that such tests in the past have been used to discriminate against minorities and women.

The vote to back dismissal of incompetent teachers was the NEA's first clear resolution on that topic, although it has long favored yearly evaluations of classroom teachers. The union has gained a reputation for obstructing dismissal of incompetents, although Futrell said yesterday that the NEA was only concerned with making sure school administrators "respect our due process rights."

The resolution said a teacher can be dismissed if "formally reevaluated and there is documentation of incompetence."

In other votes during the 123rd annual convention, the delegates:

Launched a campaign to have local NEA affiliates seek out school buildings that do not comply with federal standards on levels of cancer-causing asbestos.

Asked the executive committee and the political action committee to "explore all options" for increasing the role of members in presidential primary endorsements. Last year's endorsement of Democrat Walter F. Mondale was made by the committees, not the membership.