Senior Sergeant Anthony Bond, of Dunedin, said police were called to Mercy Hospital in Newington Ave at 7.55am on Saturday.
A 29-year-old woman was walking in and out of patients' rooms, telling people she was at the hospital for heart surgery.
She had been there on Friday causing similar disturbances.
The woman was not a patient and had no heart surgery booked, Snr Sgt Bond said.
She caused disturbances in the wards by opening patients' curtains and drinking their water.
Staff asked the woman to leave multiple times but she refused.
After her refusals, police were called and the woman was arrested.
She was bailed shortly after being taken to the police station, and she returned to the hospital that afternoon and was again disruptive.
Police were again called and she was again arrested.
This time, bail was opposed and she was held by police to prevent her returning to the hospital.
It is understood the hospital had extra security put in place in the meantime to monitor the entrance.
The woman was due to appear in court today.