In a prior decision, the ICTR Chamber II had scheduled the beginning of the trial for 3 August.
The deferral, according to the new order, was to allow the new lead counsel of the accused, Briton Peter Herbert, to adequately prepare his client's defence.
The Registry terminated the contract of the former Counsel, American professor David Thomas, following the accused's lack of confidence in his lawyer.
Herbert has already indicated, in a motion addressed on Tuesday to the Chamber, that he would not be ready on 23 September, until December or January 2010.
Arrested in Germany on 17 September 2007, the former minister has been in the custody of the ICTR since 8 October 2008, whereas his father-in-law is still at large, less than two years to the close of the tribunal.
Accused of crimes of genocide and crimes against humanity, Ngirabatware claimed his innocence during his first initial appearance on 10 October 2008 on the basis of an indictment from 1999.
Following the amendment of the text, a new appearance took place on 10 February, during which he once again pleaded not guilty.
The former minister was accused of having used public funds to finance the activities of the Interahamwe militiamen, the main armed element of the genocide.
A doctor of economics from the University of Freiburg (Switzerland), Ngirabatware was, in his country, a teacher at the National University of Rwanda (1986-1994), then Minister of Planning (1990-1994).
After his departure into exile in July 1994, he worked in various research institutes in Gabon and in France.
The Rwandan academic will be tried by a Chamber presided by the Tanzanian Judge William Hussein Sekule.
Four other ICTR prisoners, including a former minister during the genocide, are waiting to appear.
© Hirondelle News Agency