WASHINGTON (AP) _ Yat-Pang Au enrolled at the University of California at Berkeley this semester after a two-year battle against a school admissions policy that he said discriminated against Asian-Americans.

His case has drawn new attention to affirmative action programs designed to help minorities enter top colleges and universities - because in some cases they have hampered rather than helped this minority, which scholastically outperforms the general population.

Au graduated at the top of his high school class and received awards for 10 extracurricular activities. But his initial application to Berkeley was rejected two years ago, his father said, because of an affirmative action policy that put a 40 percent limit on admissions based strictly on grades and test scores.

In a single year, the number of Asian-Americans accepted as freshmen at Berkeley dropped from 24 percent to 21 percent amid cries of racism.

''I fight this not because it's my son but for Asian people as a whole,'' said Au's father, Sik Kee Au, a businessman in San Jose, Calif. ''One of the most important things in life for us is an education.''

The university has since revised its admissions policy, and the younger Au enrolled there as a transfer student this semester as a junior. His younger brother Yat Hon was admitted as a freshman.

University officials say the new admissions policy maintains high academic standards while reflecting the state's diverse population, helping blacks, Hispanics and other low-achieving groups. It has placated the once-angry Asian-American community, but Rep. Dana Rohrabacher, R-Calif., wants more.

Rohrabacher is sponsoring a resolution that would put Congress on record as opposing quotas that appear to discriminate against Asian-Americans.

''I believe that the issue here is not affirmative action but one of equal opportunity for all students,'' said Rohrabacher in a recent letter to the Asian Pacific Americans in Higher Education. ''Quotas and other forms of racial discrimination have no place in our nation's schools and for that matter anywhere else.''

University officials said the proposed resolution may hamper efforts by colleges and universities to enroll more minorities.

''It would appear that Mr. Rohrabacher is using this resolution as a way to get at affirmative action, which we obviously would totally disagree with,'' said John Cummins, assistant chancellor for public affairs.

Most colleges and universities across the nation are seeking ways to increase minority enrollment to prepare for demographic projections that minorities collectively will become the majority by the year 2000.

Enrollment of minority undergraduate students this fall at Bowling Green State University in Ohio increased 13.2 percent over last year. Blacks account for 4 percent with 636, Hispanics make up about 1 percent with 140, and other minorities, primarily Asians, have gone from 96 to 118 of the 15,978 undergraduate students.

At the University of Michigan, minority student enrollment increased by 9.3 percent this year, from 4,991 to 5,454, a record total. Officials said Asians comprise 6.8 percent of the student body (after an Asian enrollment increase of 11.1 percent), blacks 6.5 percent, Hispanics 2.8 percent and American Indians 0.4 percent.

The Chronicle of Higher Education said that in 1986, colleges enrolled 90,000 American Indians, 448,000 Asians, 624,000 Hispanics, 1.1 million blacks, 9.9 million whites and 344,000 foreign students. The schools also have instituted special programs to recruit and retain minorities.

UC-Berkeley officials insist their new admissions policy merely reflects the state's population, while upholding high academic standards. The school receives about 22,000 applications for 4,000 spaces.

Cummins said that since 1980, the state's population has increased 500,000 a year and that between now and the year 2000, there will be an additional 6 million residents, mostly minority - Hispanic and Asians particularly.

The Asian population has grown a phenomenal 70 percent since 1980 and now approaches 10 percent of the state's total.

Statistics show that Asian-Americans at UC-Berkeley had the highest graduation rates, nearly 95 percent in 1987, compared with 93 percent for whites. Other minorities, including blacks and Hispanics, had graduation rates in the low- to mid-80s.

By 1991, UC-Berkeley will admit 50 percent of its students based on grades and test scores alone. Currently, 40 percent are in this academic category.

About 45 percent of the fall freshman admissions will be based on criteria other than academic scores alone. The other criteria will include race, disability and special talents, such as in music, drama and debating.

A third category will include athletes, the poor, regardless of race or ethnicity, and older or re-entering students.

Patrick Hayashi, who works with admissions at the university, stressed that all applicants still fall within the top 12.5 percent of high school seniors.

''Some people mistakenly think that our commitment to diversify our student body has come at the expense of our academic standards. That's simply false,'' said Hayashi. ''We are doing now exactly what we've done for the past 50 years, selecting from the top.''

The elder Au said that before the recent changes, ''it was very clear'' UC- Berkeley ''had unfair practices for admissions.''

''But they are now gradually working to change that. I hope this is the beginning of opportunity.''