However, officials said this would not affect their long search for the Bosnian Serb military commander in the 1992-95 Bosnian war, as they either had to prove conclusively that he was indeed dead or arrest him if he was alive.

Serbia applied for European Union membership last year, but its progress is linked to Belgrade's full cooperation with the United Nation war crimes court for the former Yugoslavia and the arrest of remaining war crime fugitives.

Milos Saljic, the Mladic family lawyer and a former colonel in the Yugoslav military, said that the motion was "based on the fact that the general was a very sick man."

"He suffered a heavy stroke in 1996 and was later treated for various digestive tract ailments, so he could be dead now," Saljic told Reuters.

Such a declaration, if granted, would allow Mladic's wife and son to collect a state pension which has been frozen for more than three years or sell his property, including the family home in Belgrade.

Mladic was indicted 15 years ago for genocide in the Srebrenica massacre of 8,000 Muslim men and the 43-month siege of Sarajevo.

Dusan Ignjatovic, director of the government's Office for Cooperation with the Hague War Crimes Tribunal, dismissed the legal move. "This means nothing because we either have to prove physically that he is dead or locate and arrest him if he is alive," said Ignjatovic.

The chief United Nations war crimes prosecutor, Serge Brammertz, said this month he believes Mladic is in Serbia after years of hiding under protection of hard-liners and nationalists in Serbian military intelligence and state security.

Authorities in the ex-Yugoslav republic have repeatedly said that they are doing everything they can to apprehend Mladic.

Saljic said that under Serbian law, a person could be declared dead if he or she was older than 70 and there was no information about the person for more than five years. However, Mladic would turn 70 only in March 2012, which means the lawyer will seek to use another provision of the law.

Munira Subasic, head of the Women of Srebrenica association who lost her son and husband in the 1995 Srebrenica massacre, said filing such a request would be a shameful act.

"While we have been fighting for our right to locate the bones of our children for 15 years now, Serbia is finding ways of how to help the family of the most wanted war criminal accomplish their rights," Subasic said.