Presiding Judge Dennis Byron postponed the trial to September 15, 2008 when parties would meet for a Status Conference to asses the situation.
Ngirumpatse has instructed his defence team not to represent him in the case in his absence.
The other two accused in the trial are: Edouard Karemera, former Vice President of MRND and its former Secretary General, Joseph Nzirorera.
All three have pleaded not guilty to genocide and crimes against humanity.
The Chamber had expected to continue with the defense case of the accused Karemera, who was presenting his case when it was adjourned mid last July for judicial recess.
© Hirondelle News Agency