The victims were deputed for lab training at the government-run medical facility in Secunderabad, they said.
"The trainees submitted a representation to the superintendent of the hospital in the month of August 2017 levelling allegations of sexual harassment by the lab technicians," police said in a release.
An inquiry committee was set up to look into the allegations, it said.
On a specific complaint made by a trainee yesterday, a case was registered in the Chilkalaguda police station and investigation taken up, it said.
"During the investigation, the police examined as many as 14 witnesses and established prima facie case against the (four) accused employees of the hospital. All the accused persons were arrested on 02.12.2017," the release added.