The babies, all of whom were born prematurely and underdeveloped, died at the newborn unit of Tepecik hospital on Saturday and Sunday, Turkish newspapers reported, suggesting that an infection was to blame.
The local prosecutor's office on Monday ordered that five of the babies, who had already been interred before officials became suspicious, be exhumed for an autopsy, Anatolia said.
The bodies of the remaining babies were already at the local coroner's office, it added.
The head of the local health directorate, Mehmet Ozkan, told Anatolia a medical investigation was also underway to determine the cause of the deaths.
A detailed statement could be made later in the day, he added.
In remarks published in the mass-circulation Sabah newspaper, the hospital's chief physician said they suspected an infection could be behind the deaths.
"Under normal conditions, we lose five or six babies in three days and less than 20 in a month," Professor Gazi Yigitbasi said.
The NTV news channel said a team of doctors from various universities in Izmir would inspect the hospital while tests were being done on samples taken from the unit where the babies died.
The incident at Tepecik hospital is the latest in a string of deaths in recent years that have raised questions over standards in newborn units.
In August, a state hospital in capital Ankara reported that 27 newborn babies had died over a 15-day period.
The hospital said at the time the deaths were caused by a variety of reasons, including hypertension, heart failure and complications at birth. Trade union officials however blamed it on an infection triggered by poor sanitary conditions.
In 2005, eight premature babies died of a bacterial infection in a hospital in the northwestern city of Edirne, and an infection claimed the lives seven babies at a newborn unit in the central city of Kayseri.