A graffiti representing Ratko Mladic in downtown Belgrade

The defence team "respectfully moves for the disqualification of judge (Alophons) Orie in order to restore the integrity of the proceedings," said lawyer Branko Lukic in a request published on the website of the Yugoslav war crimes tribunal in The Hague.

According to the petition, presiding judge Orie cannot be impartial because he has already condemned several former subordinates of Mladic.

Orie was removed from the case of Mladic's former political chief Radovan Karadzic in 2008, after the former Bosnian Serb leader made a similar complaint.

In a 41-page document, his defence lawyers also suggested that Orie should withdraw from the case because he is the same nationality as the Dutch NATO troops who had failed to protect Muslims killed by Bosnian Serb forces in the enclave of Srebrenica in 1995.

The defence consequently called for the opening of the trial, due to begin on Wednesday, to be pushed back to allow their request to be considered.

Mladic, 70, faces 11 counts of genocide, crimes against humanity and war crimes stemming from the 1990s Balkans conflict which claimed the lives of some 100,000 people.

Mladic was arrested in May last year in northeastern Serbia and brought to The Hague, where he has since been behind bars at a UN detention unit.

The man referred to as "The Butcher of Bosnia" faces counts which include the massacre at Srebrenica in July 1995 in which more than 7,000 Muslim men and boys were murdered.