The decision to confiscate the passports of Karadzic's wife Ljiljana Zelen-Karadzic, his son and daughter Aleksandar and Sonja Karadzic-Jovicevic and his son-in-law Branislav Jovicevic was taken on Thursday following suspicions that they had been aiding the war crimes suspect evade arrest.
Bosnia's international envoy Miroslav Lajcak said in a statement that their passports had been confiscated "at the request of the International Criminal Tribunal for the former Yugoslavia and in close co-operation with relevant local law enforcement agencies".
His family said however that they had not been in contact with Karadzic since 2002. They are currently resident in the Bosnian Serb city of Pale, some 16 km (10 miles) east of the Bosnian capital, Sarajevo.
Karadzic, alongside his former military chief Ratko Mladic, has been charged with genocide over the 1995 Srebrenica murders of at least 7,500 Muslim men and boys and the 1992-95 Sarajevo siege in which some 11,000 people were killed.
A Bosnian Interior Ministry spokeswoman said the seizure of the passports would "prevent them from leaving the country."
Bosnia's Cabinet also decided to freeze assets belonging to Karadzic, Ratko Mladic, Stojan Zupljanin and Goran Hadzic. The four men are all wanted by the Hague-based International Criminal Tribunal.
