A new federal rule requiring high school non-graduates to pass standardized tests before attending college or trade school could slam the door on thousands of prospective minority and immigrant students, college officials say.

The rule took effect Jan. 1 and is aimed at curbing federal student loan defaults, which totaled $8 billion through fiscal year 1990.It requires any student lacking a high school diploma or the equivalent to pass a test from a list of federally approved exams to prove they can benefit from higher education.

The "ability to benefit" regulation targets most directly students attending the nation's for-profit and trade schools, which have among the nation's highest default rates. The rule is intended to weed out academically weak students.

The nation's 1,200 junior and community colleges also will bear the brunt of the rule since many of their students are immigrants and older learners who lack high school credentials.

College officials fear the rule could unfairly deny many students a chance at higher education because it requires even those not applying for federal loans to pass tests.

"I think it will devastate this college district," said Donald G. Phelps, chancellor of the 110,000-student Los Angeles Community College District. He said 67 percent of the district's students are minorities or foreign-born, and many are likely to fall under the new rule.

Stephen J. Blair, president of the National Association of Trade and Technical Schools, which represents 1,300 for-profit schools, called the rule "educational apartheid."

He said that more than 100,000 of the 660,000 students attending such trade schools nationwide lack high school credentials and will have to take tests or face the loss of federal aid.

Martha Bazik, president of Chicago Citywide College, said 70 percent of her 16,000 students are in basic literacy programs and lack high school credentials. Her school has a federal loan default rate of 33 percent.

But Bazik said testing is the wrong solution.

"I am not a proponent of tests anyway but especially not for adult or at-risk students who haven't been well-served by education. Tests don't measure ability to analyze, and they fall short of measuring the ability to think," she said Wednesday.