White Americans' prejudice against blacks "is at the root" of continuing housing segregation in major U.S. cities, a University of Chicago professor told Congress this week.

Douglas S. Massey, director of the university's Population Research Center, used U.S. census information to analyze housing patterns in 60 American cities.

In a study released in December, he said that, despite blacks' economic gains, they encounter much higher levels of segregation in housing than any other minority group.

Strong civil rights laws and improved economic conditions for blacks "won't accomplish desegregation {because} there is no law to force people to buy houses" in neighborhoods where they do not want to live, Massey said.

Evidence indicates that "high levels of black segregation ... cannot be attributed in any meaningful way to objective social and economic factors."

Massey appeared before the housing subcommittee of the House Banking, Finance and Urban Affairs Committee this week.

The hearing was scheduled to air Massey's testimony and to investigate fair housing law enforcement in the wake of a Los Angeles Times report that workshops on housing discrimination problems held by the Department of Housing and Urban Development were paid for by developers, real estate professionals and others who do business with the department.

Massey told the subcommittee that blacks have been unable to achieve integration in cities, are "less able than other groups to attain suburban residence, and once in the suburbs, they are still highly segregated."

He cited evidence of "harassment and intimidation of black renters or home buyers by white citizens," blacks' difficulty in obtaining mortgage loans to buy property in integrated areas and "systematically different treatment by real estate agents."

Black segregation results from both active and passive discrimination: Whites try to prevent blacks from entering white neighborhoods and, once blacks have moved in, whites avoid the areas, according to Massey.

Since passage of the 1968 civil rights law, discrimination has become subtle, to the point that blacks often do not know they are being discriminated against, he said.

Hispanics also face housing problems, being both "disproportionately poor and inadequately housed," Charles Kamasaki, of the National Council of La Raza, one of the country's biggest Hispanic organizations, told the subcommittee.

Low income alone cannot explain the difficulties, however, and "blacks and Hispanics are twice as likely as whites to be either inadequately housed or overcrowded, even when they have similar financial resources," he said.

HUD Secretary Samuel R. Pierce Jr. refused the subcommittee's request that he testify at the hearings because he said he expected a political attack from the subcommittee members.

Pierce also declined to send another HUD official in his place.

Pierce's refusal to testify infuriated subcommittee members and underlined the enmity that has existed between the HUD secretary and some subcommittee members for several years.

Pierce has not appeared before the group since March 1985, despite several invitations, and usually has sent lower-ranking department officials, according to subcommittee staff members.

Rep. Bruce A. Morrison (D-Conn.) said Pierce should be subpoenaed if he does not change his mind about testifying. Other subcommittee members agreed.

In a letter to subcommittee Chairman Henry B. Gonzalez (D-Tex.), Pierce said the hearings were unnecessary because HUD is conducting an investigation into the allegations of improprieties in financing the fair housing workshops, and would send the results of the probe to the subcommittee.

In addition, Pierce wrote, "It is my judgment that a hearing on the Los Angeles Times allegations would degenerate into a partisan attack ultimately harmful to the cause of fair housing."

A HUD spokesman said this week that Pierce expects to complete the investigation in about two weeks.

After the subcommittee's hearings this week, Gonzalez renewed the invitation to Pierce to appear before the panel, suggesting four dates in February, a Gonzalez aide said.