The Board of Deputies has sent a letter to Conservative leader David Cameron expressing concern over his party’s rightwing European alliances.
Vivian Wineman, president of the Board, wrote to Mr Cameron raising his concerns over the past political activities of Michal Kaminski and Roberts Zile, who made appearances at the Tory conference this week.
Mr Kaminski, who is Polish, is the leader of the European Conservatives and Reformists bloc at the European Parliament, of which the Conservative Party is a member. Mr Zile is the leader of the Latvian Fatherland and Freedom party.
Both came under attack from Foreign Secretary David Miliband at the Labour Party conference last week. He referred to Mr Kaminski’s "antisemitic past" and alleged that Mr Zile's party conducted annual commemorations of the Latvian branch of the Waffen SS.
Mr Kaminski had been expected to speak at a Conservative Friends of Israel event, but did not show. He did however have lunch with the group, including Israeli ambassador Ron Prosor, earlier in the day.
The Board has decided not to make its letter to Mr Cameron public, but a spokeswoman said it was about seeking reassurances about the accusations made against Mr Kaminski and Mr Zile, and was not accusatory in tone.
A Conservative party spokesman suggested that the Board’s action may have been swung by a Labour bias.
He said: "We're concerned that the politically-motivated allegations made by the Labour Party and their allies have been noted by the Board of Deputies."
"All these allegations have repeatedly been shown to be false. We will talk to the Board of Deputies about the lack of evidence behind them and their partisan nature.
“People should take account of the fact that the Polish chief rabbi has said that his remarks have been misrepresented, that the Latvian foreign minister has called David Miliband about his remarks, and that the Latvian ambassador in London has spoken to the Foreign Office about the matter."