Attorney General Griffin B. Bell is considering whether to approve an unprecedented civil suit against the city of Philadelphia in an effort to stop a history of alleged police brutality in the "city of brotherly love."

Bell raised the issue, without naming Philadelphia, in answer to question about police brutality at a press luncheon yesterday. "We're looking at the idea of filing a suit - which would be unprecendented - against a city where that's problem," he said.

He said such a suit would seek an injunction to stop "those practices and the system which allows it to go unchecked." Violations of an injunction could lead to contempt citations by judge and penalties of civil fines or, in rare cases, jail for disobedient city officials.

Department sources said later that a team of civil rights division attorneys led by Louis M. Thrasher has been studying the possibility of such a suit for several months.

Thrasher said yesterday that he was "not free to discuss what I've been doing in Philadelphia." He did say that he had been given the complete cooperation of the police department there.

City officials in Philadelphia were not available for comment yesterday because offices were closed for "Flag Day."

The U.S. Commission on Civil Rights held hearings in Philadelphia in April on allegations that the city, and Houston, had the most brutal police departments in the country.

The commission heard testimony from state and federal prosecutors who said high police officials failed to discipline officers found guilty of brutality. Six homicide detectives were found guilty of beating a prisoner in one federal case last year, for example, but were not disciplined by the department.

While the federal government has brought several cases in Philadelphia and elsewhere against individual police officers accused of brutality, until now it has not found a way to attack the problem throughout a major city.

One Justice Department official familiar with the Philadelphia investigation said yesterday, "We've been looking for years for some kind of civil remedy in cases like this. Individual prosecutions - even big ones - are only a Bank-Aid approach." The problem has been finding the specific statutory authority to bring the suit, he said.

Tony Jackson, director of the police project for the Public Interest Law Center in Philadelphia, said in a phone interview yesterday that he gave Thrasher's group evidence on 1,400 alleged police brutality cases dating back to 1973.

The Philadelphia situation is complicated, he said, by a 1976 U.S. Supreme Court decision that overruled a lower judge's order for sweeping changes in the city's police department because the alleged brutalities were not systematic.

"It appears now, as we thought, that Mr. Thrasher's investigation has found the systematic abuse that could be the basis for a suit to protect the constitutional and civil rights of victims," Jackson said.

Civil rights division attorneys reportedly met with Bell last week to discuss the possible suit. It is unclear when he might decide whether to authorize a filing.

The attorney general leaves Saturday on a two-week visit to the Soviet Union with an American Bar Association group.

Bell ordered an investigation of the Philadelphia situation last summer after being visited by groups representing alleged victims of brutality and the city police.

At the Civil Tights Commission hearings in April, Philadelphia Mayor Frank Rizzo, a former police commissioner, claimed that charges of police brutality in the city were largely "media-generated." The Philadelphia Inquirer won a Pulitzer Prize for an expose of such charges.