Jewish community leaders in Poland have demanded a "firm reaction" from President Andrzej Duda and Prime Minister Beata Szydło over a Polish MP's public use of anti-Semitic rhetoric.

Pawel Kukiz, who heads a 15-member parliamentary group including radical right-wingers, claimed Sunday that the recent opposition rallies in Warsaw were funded by a “Jewish banker.”

In an interview with a local radio station Zet Radio, Kukiz said that “apparently the march was financed somehow from the outside. 150 million PLN (38 million USD) are to be given by the Jews, the Jewish banker, in organization of the march.”

According to the station, the right-wing politician was referring to Hungarian-born American financier George Soros.

Lesław Piszewski, head of the Union of Jewish Religious Communities in Poland, warned Kukiz's remarks set a worrying precedent.

“For the first time since [Poland’s] democratic elections in 1989, a politician in parliament, who has run for the presidency, has used such obvious anti-Semitic rhetoric,” Piszewski declared.

Kukiz, for his part, has denied the accusations of anti-Semitism against him, dismissing them as "baseless."