Holocaust denier Ursula Haverbeck-Wetzel, 88, arrives for her trial at the Amtsgericht Tiergarten courthouse on October 16

A German court on Monday sentenced an 88-year-old 'Nazi grandma' to six months in jail, the fifth in a string of similar convictions for the repeat Holocaust denier.

Ursula Haverbeck has often denied the mass murder of millions of Jews by the Nazis, which constitutes incitement of racial hatred under German law.

And although she has been convicted on several occasions, she has not served any jail time, as the cases are all still under appeal.

During a public event at the end of January, Haverbeck repeated her claims, saying it was 'not true' that there were gas chambers at the Auschwitz death camp.

She also disputed the fact that 1.1 million people were killed at the concentration camp in Nazi-occupied Poland.

During her trial, Haverbeck argued that she was only quoting from a book that she was presenting at the event.

She also filed an immediate appeal against Monday's ruling.

Haverbeck (pictured) is accused of having said at a public gathering in Berlin earlier this year that the Holocaust never happened and that the gas chambers at Auschwitz are fake

Dubbed the 'Nazi grandma' by German media, Haverbeck is a notorious extremist who was once chairwoman of a far-right training centre shut down in 2008 for spreading Nazi propaganda.

She had also appeared on television to declare that 'the Holocaust is the biggest and most sustainable lie in history'.

A court spokeswoman said that Haverbeck would only be imprisoned if an appeal fails and if she is deemed fit to serve time in prison.

Haverbeck was most recently convicted of Holocaust denial in September 2016, when she was sentenced to eight months in prison for Holocaust Denial. However, she has appealed the decision.

Although Haverbeck (pictured at her latest trial) has been convicted on several occasions, she has not served any jail time, as the cases are all still under appeal

Dubbed the 'Nazi grandma' by German media, Haverbeck is a notorious extremist who was once chairwoman of a far-right training centre shut down in 2008 for spreading Nazi propaganda

Haverbeck wrote a letter in February to the mayor of Detmold when a former Auschwitz guard was going on trial there, claiming the notorious Nazi death camp was only a labour camp and called survivors 'alleged witnesses.'

She was also convicted of Holocaust denial in 2015 for a similar statement in an interview outside the trial of a former Auschwitz guard in Lueneburg.

She was sentenced to 10 months imprisonment in that case but remains free as her appeal is heard.

Haverbeck, who is a friend of Gudrun Burwitz - elderly daughter of Nazi S.S. chief Heinrich Himmler - was sentenced for sedition over the interview she gave to a TV station denying that Jews were murdered in extermination camps.

Haverbeck waits for the opening of her trial at a courtroom of the district court in Detmold, western Germany, on September 2 2016

In the interview with the ARD network she claimed the death camp of Auschwitz in Nazi-occupied Poland, where at least 1.1 million people were murdered, was 'nothing more than a labour camp.'

In Germany, anyone who publicly denies, endorses or plays down the extermination of Jews during Adolf Hitler's regime can be sentenced to a maximum of five years in jail.

It is estimated that more than six million people, including Jews, gays, Romany, the disabled and other persecuted minorities, were killed during the Holocaust.

Some 1.1 million people, most of them European Jews, were murdered between 1940 and 1945 in the Auschwitz-Birkenau camp before it was liberated.