The Navy has ordered a servicewide effort to improve treatment of women officers and sailors following reports of sexual harassment and rapes at its Orlando, Fla., training center and the Naval Academy at Annapolis, officials said yesterday.

"It is time to take stock," Navy Secretary H. Lawrence Garrett III wrote in an unusually frank memorandum distributed throughout the Navy calling for "new policies that will lead to improvement of the opportunities for women in the Navy and their quality of life."

Chief of Naval Operations Adm. Frank B. Kelso II simultaneously ordered a Navy task force to review policies and address issues of "sexual harassment, fraternization, equality of treatment and the adequacy of follow-up . . . assistance to victims of sexual offenses as well as timely investigation and disciplinary proceedings in such cases."

Garrett issued his memorandum to all Navy commands Tuesday night, the day after The Washington Post published findings by the Navy inspector general that the service's Orlando training center has had serious problems with rapes, sexual assaults and violations of "fraternization" rules and often has not sought adequate punishment of offenders.

The Florida facility includes the service's only boot camp for women recruits entering the Navy.

Congressional leaders yesterday also called for further investigations into the Navy's treatment of women after the inspector general's report and previously revealed problems of sexual harassment at the Naval Academy.

"I am very concerned about the persistent problems the Navy appears to have with treatment of its women sailors," wrote Senate Armed Services Committee Chairman Sam Nunn (D-Ga.) in a letter requesting the personnel subcommittee to investigate. "That such {sexually abusive} behavior is not dealt with more seriously than documented in the Navy inspector general's report suggests that there may be institutional problems in the Navy and its treatment of women."

Rep. Beverly B. Byron (D-Md.), who heads the House Armed Services Committee's personnel panel, said her subcommittee will conduct its investigation of problems at the training center as well as Navywide issues of sexual harassment of women and will schedule hearings on the issue.

The Navy last reviewed servicewide concerns over the treatment of women in 1987 after a Pentagon-sponsored panel reported widespread sexual harassment of women at naval bases in the Pacific region. Numerous recommendations were subsequently made for improving the professional and personal climate for women in the sea service.

The Navy planned to assess the success or failure of those initiatives next year, but accelerated the review "in part, due to the recent coverage of alleged incidents in Orlando as well as coverage of other alleged incidents of sexual harassment," a Navy spokesman said.

Earlier this year midshipman Gwen Dreyer resigned from the Naval Academy after revealing that a group of male students had handcuffed her to a urinal in a men's bathroom, taunting her as other male classmates photographed her. Several male students were disciplined, but members of Congress in hearings last summer sharply criticized the punishments as little more than wrist-slapping. The incident sparked investigations which reported serious problems of sexual harassment at the prestigious school.

The inspector general reported that 24 rapes and sexual assaults were reported at the Orlando center in the 18 months ending June 30, and that investigators substantiated six rape cases and five instances of sexual assault.

The Navy has prosecuted none of the rape cases and ordered two of the men accused of sexual assault to appear before a court-martial.

Rear Adm. Louise Wilmot, who heads the Navy's Orlando training center, this week defended her command's handling of sexual harassment, rape and fraternization cases, saying, "We think we know what we're doing. This is a good place for women in the Navy."

The inspector general also reported 13 cases in which supervisory officers or instructors violated Navy "fraternization" rules by having social or sexual relationships with young female recruits or students.