At a time when sexual integration of big city police department is almost as passe an item of conversation as blacks break into professional baseball, Philadelphia's combative Mayor Frank R. Rizzo and the U.S. Justice Department are locked in an incongrous legal battle over whether women were ever meant to be police officers.

Charges of sexism, harrassment, spying and doctoring of performance records have been brought against the department by the vcity's first group of women patrol officers only a year after they went onto the street on an experimental basis.

The Justice Department, claiming Rizzo and Police Commissioner Joseph F. O'Niel are flagrantly violating a court order, has assigned FBI agents to investigate charges that senior male officers are trying to force the women to quit the department.

Already, 22 women have transferred from patrol duty to the Juvenile Aide Division, the traditional protectorate for women in Philadelphia's police department. Another 20 women have applied for nonpatrol duties, some of them citing the pressure of what they allege is a systematic program of intimidation. There are about 8,200 men and close to 100 women on the force.

Several have resigned, and seven claim that even though they graduated from a police academy refresher course on Jan. 17, they have been reassigned there to nonspecific duties. They said they are told to sit in the ladies room for most of their shift and that they are assigned to menial chores as stuffing envelopes.

City official, meanwhile, counter that the Justice Department is trying to renege on a March, 1976, consent decree in which an outside consulting firm will determine whether women are capable of handling beat patrols.

The consulting firm's findings, city officials say, could put the lie to "undocumented" claims by police departments in other cities that women perform equally as well as men.

O'Niel, in a court deposition, said that women should not become beat officers because, "God, in His wisdom, made them different."

Rizzo, who was police commissioner previously was involved in several racial discrimination suits, has said that women are "incapable of coping with the violent criminals of today."

In a series of interviews, some women officers said male officers, reacting to Rizzo and O'Niel's hardline position, have tried to demoralize them.

Citing a departmental order not to talk to reporters about their experiences, the women demanded anonymity in unusual ways. They would talk to a reporter only by telephone, and even then referred to themselves by a prearranged shield number supplied by an intermediary.

"I don't need any more grief than I already have. I know I'm being watched for what I say," says one.

Several women complained they had been followed by police internal affairs officers in unmarked cars and gas company vehicles, looking for minor infractions. Several complained that when they participated in arrests their names were deleted from performance records, and some said the department has tried to publicize minor mistakes. One said she was forced to call everyone in her unit - even rookie male policemen - "sir."

One woman said she was threatened with disciplinary action because she took lunch break slightly than her assigned time, and [WORD ILLEGIBLE] said she had been reprimanded for exceeding her 20 minute lunch break by two minutes.

"Rizzo has said women will never make it on sector street Patrol and the commanding officers know it. The only thing we all know about Frank Rizzo is that he remembers his friends, and it is no surprise that his old police cronies are doing what they know Rizzo wants. They don't have to be told," said Helen McCaffrey, a lawyer for the dissident policewomen.

The only policewoman who would speak for attribution was Penelope Brace, an eight-year police veteran who in 1973 filed the original equal opportunity complaint that led to the lawsuit. In 1975, after the federal Law Enforcement Assistance Administration withheld $4 million from Philadelphia because of the alleged discrimination, the Justice Department joined in the suit.

Brace, one of the seven women who claim they are being "held captive" at the police academy, said she was trailed by a male internal affairs officers looking for indiscretions after she filed the complaint, and that her present "non-job" is a form of retribution.

She said that most of the 72 women still on sector patrol have been assigned to the six most dangerous districts in the city and that they are not allowed to ride with male officers in cars.

The Justice Department this week filed a motion asking that unless the next police academy class is 20 per cent female, the department not be allowed to open the class.

U.S. District Court Judge Charles Weiner, who in March criticized O'Neil for not assigning the women to units of their choice, reserved decision on the motion.

O'Neil and Rizzo, fighting the court case, declined to comment on the women's charges, but City Silicitor Sheldon Albert called the charges of harassment and spying "a lot of crap."

"The reason those women are at the academy is that they refused to go on sector patrol. They're in holding pattern.

"Sector patrol is a dreary, drudge filled job, and it is dangerous. The problem is, these women were in Juvenile Aid when rules were pretty lax and now they're having a hard time adjusting," he added.

When asked why, after so many other police departments have integrated, Philadelphia's should be so controversial, Albert said, "Because we drew the line on putting women on patrol . . . we felt our obligations to the citizens were such that we didn't want to experiment with public safety. "It's a physical matter, not a question of mentality. And we're not saying all women didn't automatically have a right for such duty."

Albert said the Justice Department should let the city finish his study.

"If they would let us get on with completing this report, then all of us in the United States would know whether women would make good police officers. If they do, then so be it. But everyone has the right to find out whether women are qualified or not," Albert said.