Former Bosnian Serb leader Radovan Karadzic asked the UN's Yugoslav war crimes tribunal on Thursday to order the Greek president to give evidence for his war crimes trial.

"Radovan Karadzic... moves for the issuance of a subpoena to Greek President Carolos Papoulias compelling him to submit to an interview conducted by Mr Karadzic's legal advisor Peter Robinson," he said in a document submitted to The Hague-based court.

Karadzic, 66, who faces genocide, war crimes and crimes against humanity charges before the International Criminal Tribunal for the former Yugoslavia (ICTY), proposed a one-hour interview at Papoulias's Athens office on April 2.

As Greek foreign minister between 1993 and 1996, Papoulias "played a prominent role in the Bosnian peace negotiations" and could testify to the various meetings and conversations they had, Karadzic said.

"Because of the religious and historical ties between Greece and the Serbs, President Papoulias was one of the few international interlocutors whom the Bosnian Serbs trusted and with whom they could speak confidentially and candidly," Karadzic said.

Karadzic, who was arrested in Belgrade in 2008, said evidence by the Greek president would include establishing his innocence for the shelling of Sarajevo's Markale market on February 5, 1994 in which 67 people died.

He added that he had sent several letters to the Greek government, which declined to his request to have Papoulias interviewed.

Once the most powerful leader among Bosnian Serbs, Karadzic, 66, faces 11 counts for his role in the Bosnia conflict which left some 100,000 people dead and 2.2 million homeless.

He wanted in particular for masterminding the killings at the eastern Bosnian enclave of Srebrenica, the only episode in the 1990s Balkans wars to have been ruled genocide by the ICTY.

His trial opened in October 2009, but has been hit by several delays since.

Karadzic has pleaded not guilty to the charges. If convicted he could face life behind bars.