The government decree was introduced last week after police conducted raids targeting senior figures including the sons of ministers and businessmen as part of a fast-moving corruption enquiry.
The decree was seen as a bid by Prime Minister Recep Tayyip Erdogan to contain the probe that poses the biggest threat to his 11-year rule.
Erdogan has swiftly responded to the investigation by sacking dozens of police chiefs and introducing measures seen by critics as an attempt to curb independent investigations by public prosecutors.
Political analysts link the high-level probe to simmering tensions between Erdogan's government and followers of influential Muslim scholar Fethullah Gulen, who lives in exile in the United States.
Gulen followers hold key positions in various government branches including the police and judiciary.