Germany's government commissioner on anti-Semitism has warned Jews about the potential dangers of wearing the traditional kippah cap in the face of rising anti-Jewish attacks.

"I cannot advise Jews to wear the kippah everywhere all the time in Germany," Felix Klein said in an interview published Saturday by the Funke regional press group.

In issuing the warning, he said he had "alas, changed my mind (on the subject) compared to previously."

Klein, whose post was created last year, cited "the lifting of inhibitions and the uncouthness which is on the rise in society" as factors behind a rising incidence of anti-Semitism.

"The internet and social media have largely contributed to this -- but so have constant attacks against our culture of remembrance."

And he suggested police, teachers and lawyers should be better trained to recognise what constitutes "clearly defined" unacceptable behaviour and "what is authorised and what is not".

His comments came just weeks after Berlin's top legal expert on anti-semitism said the issue remains entrenched in German society.

"Anti-Semitism has always been here. But I think that recently, it has again become louder, more aggressive and flagrant," Claudia Vanoni told AFP in an interview, adding the problem was "deeply rooted" in German society.

Anti-Semitic crimes rose by 20 per cent in Germany last year, according to interior ministry data which blamed nine out of ten cases on the extreme right.

Justice Minister Katarina Barley told the Handelsblatt newspaper the increase was "shameful for our country" but added that the police were "vigilant".

Vanoni also said that the proliferation of online platforms that allow people to express extremist views without inhibition while hiding behind screens had fostered the rise in cases.

The arrival in parliament of the far-right AfD, whose leaders openly question Germany's culture of atonement for World War II atrocities, has also contributed to the change in atmosphere, as has the arrival of more than a million asylum seekers, many from Muslim countries such as Syria, Afghanistan or Iraq.

Klein said that while the far-right was to blame for the vast majority of anti-Semitic crime, it was apparent that some Muslims were also influenced by watching certain television channels "which transmit a dreadful image of Israel and Jews".

ISRAEL PRESIDENT SAYS JEWS UNSAFE IN GERMANY

Israeli President Reuven Rivlin said today that Germany's warning to Jews on the dangers of wearing the traditional kippah cap were a "capitulation to anti-Semitism" and evidence Jews were unsafe there.

Rivlin said Klein's remarks "shocked" him, and while appreciating the German government's "commitment to the Jewish community," accused it of bowing to those targeting Jews in Germany.

"Fears about the security of German Jews are a capitulation to anti-Semitism and an admittance that, again, Jews are not safe on German soil," he said.

"We will never submit, will never lower our gaze and will never react to anti-Semitism with defeatism -- and expect and demand our allies act in the same way," he said.

Anti-Semitic crimes rose by 20 per cent in Germany last year, according to interior ministry data which blamed nine out of 10 cases on the extreme right.

Klein, whose post was created last year, said that while the far-right was to blame for the vast majority of anti-Semitic crime, some Muslims were also influenced by watching certain television channels "which transmit a dreadful image of Israel and Jews".

Germany has a culture of atonement over atrocities committed during World War II, during which the ruling Nazis orchestrated the murder of some six million Jews in the Holocaust.