In an attempt to halt the declining number of Blacks and Hispanics entering high-level management positions, two national business groups will sponsor a conference in Boston tomorrow aimed at increasing the number of minority students earning MBA degrees.

According to the National Graduate Management Admission Council (GMAC), which is co-sponsoring the forum with the National Black MBA Association, the percentage of Blacks in Master of Business Administration programs fell from 3.9 percent in 1980 to 3.6 percent in 1984, while the number of Hispanics dropped from 1.9 percent to 1.7 percent.

"That's not significant numerically, but if you look at the disparity between the percentage of Blacks and Hispanics in the general population and those pursuing graduate management degrees, it's alarming," said Margaret Tyler, admissions director of MIT's Sloan School of Management and a member of the GMAC.

Nationally, officials say they fear this decline in MBA minority graduates will lead to further underrepresentation of minorities in high-level career positions.

"The number of Blacks and Hispanics in the population is increasing, but there is a decrease in the number of those who are in a position to make decisions about economic welfare," Tyler said.

GMAC officials attribute the nationally declining minority MBA enrollment to several factors, including a continued lack of minority role models in management positions, decreased federal student aid and decreased minority representation at the undergraduate level.

But officials at Harvard Business School, which is not a member of GMAC and does not use standardized GMAC tests in the admissions process, said minority representation in the Harvard MBA program has increased and recruiting efforts remain strong.

"In an [MBA] program, you hope to have representation that mirrors representation in society as a whole," said the associate director of admissions at the B-School, James S. Feinson. "We're trying to reach strong minority candidates and encourage them to apply."

But many experts say minority representation must be increased at the undergraduate level to provide a qualified pool of MBA applicants.

"The funnel to business school begins at the college level, and undergraduate institutions aren't accepting as many Blacks," said the president of the Afro-American Student Union at Harvard Business School, Arnold J. Lewis, a second-year graduate student.

"This conference provides them with an opportunity to meet role models from the Black and Hispanic Communities that have obtained an MBA and advanced their careers in management," said Angela M. Airall, GMAC national director of project development.

The free three-hour conference, to be held Saturday morning at the Boston Park Plaza, will include panels and discussions on minority enrollment in MBA programs and career opportunities for minority MBA graduates. It is one of 10 conferences being held nationwide.