A 96-year-old German convicted over his role in the murders of 300,000 people at the Auschwitz death camp in Nazi-occupied Poland has filed a plea for clemency, a regional justice spokesman said today.

Oskar Groening, known as the 'bookkeeper of Auschwitz', was sentenced to four years in prison in 2015 for being an accessory to murder at Auschwitz.

He has not yet started his sentence due to a dispute about his health.

In December, Germany's constitutional court ruled Groening must go to jail, rejecting arguments from his lawyers that imprisonment at his advanced age would violate his right to life.

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Oskar Groening was known as the 'bookkeeper of Auschwitz' for his job counting cash taken from victims of the notorious camp in Poland during the Second World War. He is pictured here at his trial in 2015

SS Sergeant Oskar Groening - known as 'the bookkeeper of Auschwitz' - was on trial charged with complicity in the killing of 300,000 Jews at the Nazi extermination camp

Christian Lauenstein, spokesman for the justice ministry in the northern state of Lower Saxony where the 2015 trial took place, said Groening's plea for clemency had been passed on to public prosecutors.

He added: 'A plea for clemency does not have a delaying effect such as on starting the prison sentence.'

The public prosecutor's office was not immediately available to comment.

Groening's court battle was seen as one of the last major trials related to the Holocaust, during which some 6 million Jews were murdered by Adolf Hitler's regime.

Oskar Groening, 96, was sentenced to four years in 2015 after being found guilty of being an accessory to the murder of 300,000 Jews in Auschwitz between May and June 1944

In December, Germany's constitutional court ruled Groening must go to jail, rejecting arguments from his lawyers that imprisonment at his advanced age would violate his right to life

Prosecutors said Groening - who did not kill anyone himself while working at Auschwitz - had helped support the regime responsible for mass murder by sorting bank notes seized from trainloads of arriving Jews.

Groening admitted he was morally guilty for the work he carried out at Auschwitz, which included sending bank notes he found in Jews' luggage to SS offices in Berlin, where they helped to fund the Nazi war effort.

Although Groening did not kill anyone himself while working at Auschwitz, in Nazi-occupied Poland, he helped support the regime responsible for mass murder by sorting bank notes seized from trainloads of arriving Jews.

He was an enthusiastic Nazi when he was sent to work at Auschwitz in 1942, at the age of 21.

SS officer Oskar Groening was an enthusiastic Nazi when he was sent to work at Auschwitz in 1942, at the age of 21

He came to attention in 2005 after giving interviews about his work in the camp in an attempt to persuade Holocaust deniers that the genocide had taken place.

Some six million Jews were murdered during the Holocaust carried out under Adolf Hitler.

Following his trial in 2015 Jewish groups and Holocaust survivors welcomed the four-year jail term given to the 'Bookkeeper of Auschwitz', saying there is 'no statute of limitation' for those who inflicted Nazi horrors during the Second World War.

Dr Moshe Kantor, President of the European Jewish Congress, said the verdict and trial had been of 'historic significance'.

He said: 'Although more than 70 years have passed since the liberation of the Nazi death camps, this trial reminds us that there is no statute of limitations for those responsible for Nazi horrors and demonstrates the constant need to guard against anti-Semitism, racism and hate.

'We welcome the opportunity it provides for us to educate a generation that is all too distant from the horrors of the Holocaust.'