The French News Agency (AFP) Tuesday quoted Prosecutor Magnus Elving as saying that the trial of the man, whose name could not be disclosed, should run from November to May.
"He was arrested at the end of 2011 and has been held in detention since then, and I think he should be charged in November," Elving is quoted as saying. "It's the first time someone faces trial for genocide in Sweden,” he added.
The prosecutor told the AFP that Rwanda had asked Sweden to extradite the man, but Stockholm could not comply with the request because the man obtained Swedish citizenship in 2008.
Elving pointed out, however, that part of the trial would take place in Rwanda if Kigali authorises the court to hear witnesses there. He said it would be the first time a Swedish trial to be held partly abroad.
The man is suspected of "the most serious crimes": genocide and crimes against international law. He has been in Sweden since 2007, when he joined his family and obtained a residency permit based on family reunification grounds.