Nearly 70 years after the end of the Holocaust, in which some 6 million Jews as well as Roma, homosexuals, disabled and political opponents to the Nazis were put to death, most suspects have either died or are unfit for trial.
The court in the northern city of Lueneburg did not identify the accused who will be tried on charges of being an accessory to the murder of 300,000 people, however the man has been previously identified as Oskar Groening.
Hanover prosecutors say the man is believed to have worked as an SS guard at the camp in occupied Poland between September 1942 and October 1944, where he was in charge of counting and managing the money seized from those deported to Auschwitz.
The charges relate to a two-month period between May and July 1944, when an estimated 137 trains arrived at the camp carrying 425,000 people, mostly from Hungary. At least 300,000 of them were murdered immediately.
"The accused knew that, as part of the selection process, those not chosen for work and told they were going to the showers were really going to the gas chambers where they would be put to death in an agonizing manner," the court said in a previous statement issued in September.
Some 16 survivors or relatives of survivors have come forward, the court said. Eight have been accepted as witnesses.
Groening himself has openly talked about his time as a guard and said while he witnessed horrific atrocities, he didn't commit any crimes himself.
In 2005, he told Der Spiegel magazine he recalled one incident on "ramp duty" when he heard a baby crying. "I saw another SS soldier grab the baby by the legs..." he said. "He smashed the baby's head against the iron side of a truck until it was silent."
Groening, who lives in the Hannover area, is one of some 30 former Auschwitz guards who federal investigators recommended last year that state prosecutors pursue charges against under a new precedent in German law.
Groening is the fourth case investigated by Hannover - two have been shelved because the suspects have been deemed unfit for trial, and one was closed when the suspect died.
Thomas Walther, who represents 20 Auschwitz victims and their families as co-plaintiffs in the case against Groening as allowed under German law, said it's their last chance "to participate in bringing justice to one of the SS men who had a part in the murder of their closest relatives."
While time is running out for bringing surviving war criminals to justice, Nazi-hunting groups such as the Simon Wiesenthal Center are pushing for the thousands who staffed the death camps and helped transport Jewish victims across Europe to be pursued before it is too late.
Reuters and The Associated Press contributed to this report.