The German government's anti-Semitism commissioner said Friday he is "dismayed" by claims of hostility experienced by fans of Israeli champions Maccabi Haifa during a European football match in Berlin.

Haifa fans said they were subjected to anti-Semitic insults from some Union Berlin supporters during a Europa Conference League match at the city's Olympic Stadium, where the hosts won 3-0 on Thursday.

"The anti-Semitic incidents at yesterday's match... show that hostility towards Jews is still widespread in football," Felix Klein, Germany's commissioner for Jewish Life and the Fight against anti-Semitism, told the Funke media group.

This was the first time an Israeli team has played at Berlin's Olympic Stadium, which was built during the Nazi era.

"I am dismayed that instead of fairness and respect, hatred and violence emanated from German fans, especially at this historically-charged venue," added Klein.

His comments come after the Youth Forum of the German-Israeli Society Berlin-Potsdam told of ugly scenes in the stands.

"On the terraces, we were threatened by Union fans, pelted with beer", the Forum wrote on Twitter, adding that members of their group were subjected to anti-Semitic insults "among other things".

The Forum also alleges that "a Union fan tried to set fire to the Israeli flag... which was fortunately quickly prevented by civilian police officers".

On Friday morning, the group tweeted: "Thank you for the wave of solidarity online and to the Union fans who showed solidarity with us in the stadium."

Union asked for help via Twitter to identify the alleged perpetrators.

In a statement, the Berlin club apologised for the behaviour of some fans and said they are helping police investigate.

"This behaviour is shameful and intolerable," said Union president Dirk Zingler.

"We apologise to those affected... we will never tolerate discrimination in our ranks.

"It is important to remain vigilant and to work tirelessly against it."

The match was switched from Union's Alten Foersterei ground to the Olympic Stadium, home of rivals Hertha Berlin, to meet UEFA requirements.