Among the cases highlighted was an officer who was accused of indecently assaulting several women while they were held in cells and a policeman who offered to help a woman special constable join the force in return for sex.
The Police Complaints Authority's annual report, published yesterday, also expresses concerns about the record number of deaths in custody and issues warnings about the excessive use of CS spray and batons.
On the issue of sexual harassment, the PCA noted: "Allegations of sexual harassment by police officers have been the subject of a growing number of cases dealt with by the PCA over recent years."
It went on: "... the most disturbing came from women whose vulnerability had been exploited by police officers to whom they had turned for help.
"In some cases ... women complaining of harassment had sought police protection only to suffer the same treatment from the officer supposed to be assisting them."
It added that allegations by women officers had been made against colleagues for harassment at "police stations; in police vehicles; during training courses; or while carrying out surveillance operations".
In the year up to March the PCA dealt with 73 complaints of sexual assault, of which only nine resulted in a punishment. The number of incidents of sexual harassment are not collated separately but are part of the 1,455 cases of general harassment.
The report concluded that while these type of complaints make up only a tiny proportion of their workload "they do suggest that some police officers still display an outdated and unacceptable attitude towards women and that a few are prepared to betray their position of trust for personal sexual gratification".
PCA deputy chairman John Cartwright said that much of the sexual harassment was by officers in specialist squads.
The report also noted that it had to deal with a record number of deaths in custody - there were 56 in the past year, six of whom were black.
Better training for police custody officers and surgeons should have saved some of the lives, the PCA believes.
The PCA also highlighted the 254 complaints received about the use of CS spray, saying in some cases its use was "neither justified nor appropriate".
Last year the PCA considered 4,390 fully-investigated cases of complaints against police. These led to police officers being charged with 237 disciplinary offences and 892 cases of warnings or admonishments being issued. Eighteen officers were charged with criminal offences.