Demjanjuk's son tried to prevent his Ukrainian-born father's extradition to Germany, saying he was dying of leukemic bone marrow disease.
"With less than a year and a half for my father to live, a career-seeking German prosecutor is hastily pressing forward with a 100 per cent politically-motivated effort to blame Ukrainians and Europeans for the crimes of the Germans," John Demjanjuk Jr said in a statement.
However, it remains unclear when the trial will take place.
Margarete Noetzel, a spokesman for the state prosecutor's office, said: "It is not yet possible to say when a trial would begin. Any speculation would just be like reading tea leaves.
"The prosecution's charges must be admitted by the court. Then the defence could present objections. It is going to last a while."
Photographs of Demjanjuk being taken from his home in Ohio by immigration officials in April appeared to show that he was seriously ill and in considerable pain.
But other photographs released by the US government showed Demjanjuk just several days earlier getting into his car unaided.
"He is not typical for his age ... he is in better shape than usual for an 89-year-old..."
deputy prison director
Demjanjuk denies being a guard at the camp, saying that he was a Red Army soldier who spent the second world war as a Nazi prisoner-of-war.
But documents obtained by US justice authorities include a photographic identity card which, they say, shows that Demjanjuk worked at the Sobibor death camp.
They say they have written transcripts of witness testimony placing him at the camp and reports that he was trained at a facility for Nazi guards in Trawniki, Poland.
Demjanjuk, who tops the Simon Wiesenthal Center's list of its 10 most-wanted suspected war criminals, has previously faced attempted prosecutions from courts and government officials in more than five countries on three continents.
He spent five years on death row in Israel before the verdict against him was overturned in 1993.
At the time, Israel accused Demjanjuk of being "Ivan the Terrible," a particularly brutal guard who was said to have hacked at naked prisoners with a sword, but Israel eventually concluded it had the wrong man.
Munich prosecutors say it falls on the German city to try him because he had been registered as living there after the second world war.
The day after his arrival at the Stadelheim prison near Munich, medical officials there declared him fit enough to remain in custody.
Jochen Menzel, the facility's deputy prison director said then that Demjanjuk
was in strikingly good condition.
"He is not typical for his age ... he is in better shape than usual for an 89-year-old," he told German news channel N24.
Charges of accessory to murder carry a maximum sentence of up to 15 years in jail under Germany's justice system.