The Reagan administration yesterday announced the firing of three members of the U.S. Commission on Civil Rights and named their replacements, all of whom have substantial credentials and agree with the president's opposition to racial quotas.

The nominees are Morris B. Abram, 64, former president of Brandeis University; John H. Bunzel, 59, a senior research fellow at the Hoover Institution at Stanford University and former president of San Jose State University, and Robert A. Destro, 32, a law professor at Catholic University.

In an interview in the Roosevelt Room of the White House with about 20 reporters from the major networks, the news magazines and a number of newspapers, the nominees, all of whom are Democrats, expressed their opposition to quotas and reservations about the use of affirmative action or busing.

This was an apparent attempt to counter criticism that the administration is trying to stack the commission with members who reflect only President Reagan's views. The White House also issued a handout stressing their academic and civil rights credentials.

They did not meet with Reagan, however.

"The high quality of these appointees underscores the president's dedication to the Commission on Civil Rights and to advancing the civil rights of all Americans," said David R. Gergen, the White House communications director, before introducing the nominees.

However, the response by civil rights activists and the commissioners the administration is ousting was that the administration is violating the commission's independence.

The three outgoing commissioners are Mary Frances Berry, former assistant secretary of education in the Carter administration; Rabbi Murray Saltzman of Baltimore, and Blandina Cardenas Ramirez, a San Antonio educator.

"This is a perversion of the integrity and independence of the commission," said Berry, who will be replaced by Abram if his nomination is confirmed by the Senate. "They want the commission to reflect only what they want to see, and they are breaking the mirror they have now because they don't like to see their warts."

"The president's attempted wholesale replacement of the United States Civil Rights Commission seriously jeopardizes the independence, the integrity and the effectiveness of the commission . . . ," said Ralph Neas, executive director of the Civil Rights Commission.

The question of whether the administration is compromising the commission's independence stalled three nominations the administration sent to the Senate last year, including that of Destro. The nominations never came to a vote on the Senate floor.

Meanwhile, the Civil Rights Commission yesterday sent a letter to the White House, signed by Chairman Clarence M. Pendleton Jr., a Reagan appointee. It questioned the president's nomination of Linda Chavez as the commission's staff director.

A majority of the commissioners, Pendleton wrote, have "reservations" about whether Chavez, currently an assistant to the president of the American Federation of Teachers, has "sufficient managerial experience."

At the White House, Bunzel cited polling data that most Americans supported Allan Bakke, a white student who challenged racial quotas in order to get into the University of California medical school, as evidence of widespread national oppostion to quotas.

"I think that if colleges, for example, decide that there needs to be preferential treatments with quotas for certain groups that the American people very clearly--and I give you the example of the Bakke case because it was so much in the headlines at the time--the American people again . . . support the idea that there ought not be preferential treatment with racial quotas for one group."