The head of an ultra-conservative Catholic sect has attacked the Vatican for the "excessive sensibility" shown to the Jewish world following comments made by a Holocaust-denying priest.

Bishop Bernard Fellay, superior general of the Priestly Fraternity of Saint Pius X (SSPX), told the Italian news agency Apcom that he felt "embarrassed" about the Holy See's behaviour when it emerged last January that Richard Williamson, a member of the conservative sect, denied that millions of Jews were murdered in Nazi concentration camps, as well as denying the existence of Nazi gas chambers.

Fellay also said Jews should not concern themselves with church affairs, referring to an outcry over a prayer that called for their conversion to Roman Catholicism.

In the wide-ranging interview, given last Friday, he said: "It is not their religion. Leave us alone. They are matters which concern the Catholic church. If we wish to pray for the Jews, we will pray for the Jews in the manner we see fit. I do not know if they pray for us, but I would say that this is their problem."

Williamson's comments, made in November 2008, during a Swedish TV interview, coincided with the lifting of an excommunication on Williamson and his SSPX colleagues. Intended to be an olive branch for disenfranchised traditionalists and a step towards unity with the breakaway group, the lifting of the excommunications instead became one of the most challenging periods of Benedict's four-year papacy. He drew heavy fire from rabbis around the world and the uproar prompted him to publish a letter acknowledging his mistake and reorganise key departments in the Roman curia.

Fellay played down the Williamson furore. "He [Williamson] is a completely marginal problem. What he said has no relation whatsoever with the crisis of the church, the core issue with which we have dealt for 30 years, it is a historical matter. The question of knowing how many and in what way the Jews were killed is not a matter of faith, it is not even a religious matter, it is a historical matter."

He said Williamson's removal from the SSPX was temporary.

"It is not to be exaggerated … at the moment, I see no grounds for expulsion. It depends on him, on the situation in which he placed himself … he has seriously damaged his reputation. He has already been sufficiently punished, pushed to the margin, with no position."

Relations between SSPX and the Holy See have been strained since its founder, Archbishop Marcel Lefebvre, consecrated four bishops in 1988 without papal permission. The society's leadership has also continued to denounce Vatican II, which introduced doctrinal and disciplinary reforms in the Catholic church.

Despite the recent tensions caused by the Williamson saga and a spate of ordinations decried by the pope as illegal, Fellay suggested that a meeting with Vatican officials could take place this autumn.