A German federal court has upheld the conviction of Auschwitz death camp guard Oskar Groening, who admitted witnessing murders but not taking part.

The verdict overturns a 1969 ruling that being a staff member at Auschwitz was not enough to secure a conviction.

Nazi hunter Efraim Zuroff said it was the biggest change in years.

Groening, 95, who was known as “the bookkeeper of Auschwitz”, had appealed against a four-year jail term handed down for being accessory to murder.

“This is a very dramatic and significant change in German prosecution policy,” Mr Zuroff, the head of the Simon Wiesenthal Center in Israel, told the BBC.

Germany’s Federal Court of Justice (BGH) upheld the acquittal 47 years ago of an SS dentist at Auschwitz, arguing that working at the death camp or knowing about the mass murders was not sufficient proof of guilt.

For decades, thousands of ex-Nazis who took part in the Holocaust escaped conviction. Monday’s ruling sets a precedent for pursuing suspects, now in their nineties, accused of serving in death camps.

Campaigners said the federal court’s ruling also cleared the way for prosecutions of ex-members of the Nazi mobile death squads known as Einsatzgruppen, which operated in Eastern Europe. They believe at least eight suspects could now be accused of murder because their membership of the death squads would be sufficient proof.