The Pope's second-in-command has defended the Vatican's decision to put Pius XII, the controversial wartime pontiff, on the road to sainthood, describing the title of John Cornwell's 1999 biography of Pius, Hitler's Pope, as "outrageous".

Speaking at a conference marking the 50th anniversary of Pius XII's death, Cardinal Tarcisio Bertone, the Secretary of State, said descriptions of Pius XII "as indifferent towards the victims of the Nazis" or as "Hitler's Pope" were "outrageous and historically unsustainable.''

The anniversary has revived the controversy over Pius XII's alleged silence over the Nazi Holocaust. Last week Rabbi David Rosen, head of the The International Jewish Committee for Interreligious Consultations, said the organisation had suggested to Pope Benedict XVI that Pius's beatification - the step before canonisation - should be shelved until archives relating to his wartime record were fully available for study. Benedict had replied that he was ''seriously considering'' a delay, Rabbi Rosen said.

Last week Vatican officials said it would take ''at least six to seven years'' to organise the files. The Pope praised Pius XII at a Mass on the anniversary of his death last month, saying his wartime predecessor had saved as many Jews as possible and had failed to speak out more than he had over the Nazi Holocaust in order not to make the plight of the victims of Nazism even worse.

Last month Yitzhak Herzog, the Israeli minister for social affairs, described the beatification plans as ''unacceptable', saying Pius XII had betrayed the Biblical principle of ''not keeping silent when blood is spilled''. A group of Jewish and Catholic scholars also called for beatification to be put on hold in a letter to The Times.

Pope Benedict is said to want to visit Israel, but cannot do so as long as the controversy rages. The Vatican wants an exhibit at Yad Vashem, the Holocaust Museum in Jerusalem, accusing Pius XII of silence in the face of the Holocaust to be removed.

At last month's synod of bishops in Rome Rabbi Shear Cohen of Haifa, the first Jewish leader to address a Roman Catholic synod, said he would not have accepted the invitation if he had realised the gathering would coincide with the Pius XII anniversary celebrations.

Cardinal Bertone however said the row was increasingly incomprehensible, and that Pius XII was the victim of ''a defamatory legend". He declared that procedures for beatification and canonisation were "the exclusive competence of the Holy See".