Several hundred rabbis are in Poland this week for a conference to discuss issues including the Dutch ban on kosher slaughter of animals.
It is the largest gathering of its type since Poland's Jewish community was decimated by the Nazis.
At the Warsaw meeting of the Conference of European Rabbis' (CER), Jewish leaders will be examining whether Jewish rights are under threat in Europe and how to defend them. In particular, the rabbis are looking at how to challenge the shechitah ban, which won the support of the Dutch parliament earlier this year.
CER President Rabbi Pinchas Goldschmidt said his organisation would not rest "until this discriminatory, intolerant and hateful bill" was overturned. Shechitah was prohibited by the Nazis when they occupied Poland.
Poland's chief rabbi, Michael Schudrich, said: "Although no one's claiming that Holland is Nazi, it certainly does trigger in us very bad memories."
The ban on religious slaughter requires the approval of the Dutch upper house of parliament, which will vote on the bill next month.