A 94-year-old former Auschwitz guard has been convicted of being an accessory to the murder of at least 170,000 people, at the end of what is likely to be one of Germany's last Holocaust trials.

Reinhold Hanning was sentenced to five years' jail for facilitating the slaughter at the concentration camp in Nazi-occupied Poland.

The nearly four-month long trial included testimony from around a dozen Holocaust survivors, many of them extremely elderly, who detailed their horrific experiences, recalling piles of bodies and the smell of burnt flesh in the death camp.

The defence had said Hanning should be acquitted as the former SS officer had personally never killed, beaten or abused anyone.

Hanning, seated in a wheelchair, remained silent and emotionless for much of the trial, avoiding eye contact with anyone in the courtroom.

He spoke at the end of April, apologising to the victims and saying that he regretted being part of a "criminal organisation" that had killed so many and caused so much suffering.

"I'm ashamed that I knowingly let injustice happen and did nothing to oppose it," he read from a prepared speech. 

Hanning was not charged with direct involvement in any killings.

But prosecutors and dozens of joint plaintiffs from Germany, Hungary, Israel, Canada, Britain and the United States said he had helped Auschwitz function.             

A precedent was set in a similar case in 2011, when camp guard Ivan Demjanjuk was convicted.

Last year, Oskar Groening, known as the "bookkeeper of Auschwitz", was sentenced to four years in prison after he was convicted of being an accessory to the murder of 300,000 people.             

None of the convictions are definitive.

Demjanjuk had appealed but died before the German Federal Court of Justice ruled on the case, and the court is still considering an appeal filed by Groening.             

Both sides in Hanning's case have a week to appeal the verdict.

Germany is holding what are likely to be its last trials linked to the Holocaust, in which the Nazis killed more than six million people, mostly Jews.

Besides Hanning, one other man and one woman in their 90s are accused of being accessories to the mass murder at Auschwitz.

A third man who was a member of the Nazi SS guard team at Auschwitz died aged 93 in April, days before his trial was due to start.