THE World Jewish Congress (WJC) has opened in Budapest with hundreds of representatives of worldwide Jewish communities in attendance, even as Hungary has come under fire for rising anti-Semitism.

In a speech to some 500 delegates attending the meeting, Hungarian Prime Minister Viktor Orban, who has been accused of turning a blind eye to recent racist incidents, insisted that anti-Semitism was "unacceptable and intolerable".

"Hungary has a moral duty to have zero tolerance of anti-Semitism," he added.

"There is no freedom without human dignity, we won't tolerate anyone offending the dignity of any ethnic or religious community," he also said, noting that the new constitution introduced last year provided protection and dignity for all minorities in Hungary.

The WJC reacted critically however to Orban's comments, expressing "regret" that he did not address recent incidents.

"Nor did he provide sufficient reassurance that a clear line has been drawn between the government and the far-right fringe," it said in a statement following Orban's speech.

"Actions speak louder than words, no matter how well intended they are," it added.

Anti-Semitism in Hungary has been on the rise in recent years, and the WJC meeting was taking place amid tight security.

Recent anti-Semitic incidents include Hungary's chief rabbi being verbally abused on a Budapest street, anti-Semitic chants at a football match against Israel and pig's trotters being placed on a statue of Raoul Wallenberg, the Swedish diplomat who saved thousands of Budapest Jews in World War II.

On Saturday, hundreds of Hungarians also gathered in downtown Budapest for an anti-Zionist protest organised by the openly anti-Semitic Jobbik party.

Introducing Orban to the podium, WJC president Ronald Lauder urged: "Hungarian Jews need you to take a firm and decisive lead".

"They need you to take on these dark forces. They need you to be pro-active. They need your leadership in this fight."

Peter Feldmayer, head of Hungary's largest Jewish body MAZSIHISZ, added that "Jews of the world must unite their forces".

"This day shows us that we are not alone, we are all listening to each other no matter where we may be living across the globe," he told the delegates.

While he acknowledged Orban's role in promoting Holocaust memorials, he noted that Hungary had a "vindictive (anti-Semitic) minority".

"You have come to a country which... does a tremendous lot to keep the memory of the Holocaust alive... but whose Jewish community is again under threat by horrific ideologies and acts," Feldmayer said.

The conference will begin properly on Monday with a speech by German Foreign Minister Guido Westerwelle, followed by debates on Middle East peace prospects and the rise of neo-Nazism in party political systems in Europe.

In Austria where he attended the anniversary of the liberation of the former Nazi concentration camp Mauthausen, President Janos Ader noted Sunday: "History teaches us never to make concessions to those forces which created the inhuman dictatorships of the 20th century."