Another 77 Istanbul officials also face arrest, with a total of 112 warrants issued for current or former employees of several district authorities, Anadolu news agency reported.
They are accused of links to US-based preacher Fethullah Gulen, whom Ankara blames for orchestrating the bloody coup, charges he fiercely rejects.
They allegedly used Bylock, a messaging app used by the July 15, 2016 putsch suspects.
They are accused of "membership in an armed terror group," Anadolu reported.
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The suspects are also accused of using Bylock, it added.
The arrests follow last month's resignation of Istanbul mayor Kadir Topbas, after 13 years in the key post.
Topbas, 72, did not give any reason for his resignation from the job which President Recep Tayyip Erdogan himself held from 1994 to 1998.
The former mayor found himself in a tricky situation after the coup, with police briefly arresting his son-in-law, a businessman, for alleged links to Gulen.