International Criminal Court (ICC) judges Tuesday postponed a hearing to confirm charges against Rwandan rebel leader Callixte Mbarushimana after his lawyers accused prosecutors of denying their client access to certain documents and audio files.

"The Chamber feels compelled to postpone the hearing in the wake of both parties' failure to handle their pre-trial obligations in a manner befitting the professionalism demanded when litigating before the International Criminal Court," said a ruling made public less than 24 hours before the hearing was due to start. A three-judge bench then postponed the case to September 16, 19 and 20.

Judges granted an 11th-hour request by Mbarushimana's lawyers who said prosecutors failed to give them versions in French and Kinyarwanda of certain transcripts that currently exist in English only. The court said the defence has "not been able to appropriately process thousands of pages of important information."

"The Chamber is of the view that the best course to ensure a fair and expeditious conduct of proceedings leading to the confirmation hearing is to postpone the commencement of the hearing for a reasonable time," they added.

Mbarushimana, the man identified as executive secretary of the FDLR rebel group, is facing a hearing before ICC judges for his alleged role in the murder, rape and torture of Congolese civilians in 2009.

The former computer technician faces five counts of crimes against humanity and six of war crimes over crimes committed in 2009 in the eastern Democratic Republic of Congo. He was arrested on an ICC warrant in October last year in Paris, where he had been living as a political refugee since 2002, and was delivered to the world court in January.

Imprisoned at the UN's detention centre in The Hague, he made an initial appearance before the ICC on January 28 when he protested his innocence. (AFP)