Ministry spokesman Zlatko Mehun said that Margetic was arrested on an order from the Zagreb County Court, but that he did not know the reason.
Margetic was arrested while parking his car near the police station in Slavonski Brod, Mehun said.
Local police official Andjelko Pavlovic confirmed the arrest, adding that police did not use means of coercion.
Margetic's attorney Kresimir Pencinger told reporters after a two-hour meeting with his client that Margetic had contacted the Zagreb County Court and the Police Department during the day. He reported to the police department in Slavonski Brod as agreed with the Zagreb County Court and the Police Department, because he was on a trip, the attorney said, adding that he did not have more detailed information.
This morning Margetic refused to collect at Zagreb's County Court an injunction from the Hague war crimes tribunal, which allegedly prohibits him from publishing a list of protected witnesses, claiming the injunction clashed with Croatian laws and the constitutional law on cooperation with the UN court.
The County Court's Presidency said earlier that it would notify the Justice Ministry, which would notify the Hague tribunal.
Margetic told reporters he saw the injunction and that it banned him from publishing a list of 102 protected witnesses from the Tihomir Blaskic trial. He said he published the list on an Internet portal via an American server and that the portal was closed down a few days ago at the order of the Hague tribunal.