After being on the run for two decades, Kayishema was apprehended on May 24 under a false identity on a grape farm in South Africa, thanks to the information provided by refugees working there.
Prosecutors have now raised the number of charges against him from five to 54, encompassing fraud and immigration offences.
Kayishema, who had been a fugitive since 2001, was indicted by the International Criminal Tribunal for Rwanda (ICTR) for his alleged role in ordering the massacre of 2,000 people sheltering in the Nyange Catholic Church.
During a recent court hearing on May 26, he denied any involvement in the genocide but expressed remorse for the killings.
The South African National Prosecuting Authority (NPA) alleges that Kayishema used a false identity to seek asylum and refugee status in South Africa, although he has yet to respond to these charges in court.
The case has been adjourned until June 20 to allow Kayishema's defence team to consult, during which he may apply for bail. If convicted of some of the local charges, he could face imprisonment of up to 15 years.
Additionally, Kayishema is expected to face extradition to Rwanda for trial on the ICTR genocide indictment, although the extradition proceedings have not yet commenced.
The Rwandan genocide, orchestrated by an extremist Hutu regime, resulted in the deaths of approximately 800,000 ethnic Tutsis and Hutu moderates.
Local officials and ordinary citizens actively participated in the meticulously executed genocide within the rigidly hierarchical society of Rwanda.
Kayishema's arrest now leaves only three fugitives indicted by the ICTR whose whereabouts remain unknown.
(Reuters/NAN)