"We believe that these auxiliaries were used in particular during the so-called Hungarian action in support of Birkenau," said prosecutor Andreas Brendel.
Leon Schwarzbaum, a 94-year-old Auschwitz survivor from Berlin, is scheduled to testify against Hanning.
He said: "I think the people responsible for helping make the whole apparatus function, even if they were a tiny gear in the machine, should be convicted."
The trial, which is taking place in Detmold, Germany, was moved to the city’s chamber of industry and commerce because of the large number of observers and reporters.
This is the latest in a series of recent trials against former Nazi camp guards.
In September, a 91-year-old woman was charged with 260,000 counts of accessory to murder on allegations she was a member of the Nazi SS who served in Auschwitz, while the so-called Bookkeeper of Auschwitz, Oscar Groening, was jailed last July for his role in 300,000 deaths.
