Amsterdam - Defence lawyers have challenged the war crimes case against Congolese rebel warlord Jean-Pierre Bemba, forcing the start of his trial to be postponed until July 5, the International Criminal Court said.

The trial was initially due to start on April 27, but the Hague-based ICC said on Monday a status hearing will be held on that date instead to discuss the defence's challenge to the admissibility of the case against Bemba.

Bemba, the defeated contender in the Democratic Republic of Congo's 2006 presidential election, is accused by the ICC of leading Congolese rebels who waged a campaign of rape and torture in the Central African Republic in 2002-03.

Bemba, who was arrested in Belgium in May 2008, has denied all charges.

The defence requested the dismissal of the case on February 25 on grounds including an abuse of process.

Bemba, the highest-profile suspect so far brought before the court, is facing trial on two counts of crimes against humanity and three counts of war crimes at the ICC, the world's first permanent court established to try war crimes.

Charged with murder, rape and pillage in the Central African Republic, he was transferred to the court on July 3, 2008.

A decision on the defence's request to have the case dismissed will be taken after the April 27 status hearing.