As Pius XII's canonisation is considered, Nazi hunters want to see files on alleged links between Vatican and war criminals

The pope's visit to Jerusalem this weekend has given fresh hope to campaigners – some of whom are close friends of the pontiff – who believe that he might use the occasion to open the Vatican's secret Holocaust-era files.

Among them is Efraim Zuroff, chief Nazi hunter of the Simon Wiesenthal Centre and director of its Jerusalem office. Zuroff told the Guardian: "Giving full access to the Vatican archives from the Holocaust would be a very important step in facilitating a truthful evaluation of several subjects, among them what the Vatican knew about the Holocaust and when they received that information."

Pope Francis will soon have to decide whether Pius XII, the controversial wartime pope who is accused by some of not having spoken out publicly against the mass murder of Jews, should be canonised before the Holocaust files are opened.

Although the Vatican many years ago announced a slow timetable for the release of the documents, it is believed that Pope Francis may now speed up that schedule as a gesture of goodwill towards the Jewish community. He had voiced his support for making the files public before ascending the papal throne.

Abraham Skorka, an Argentinian rabbi who is a longtime friend of the pope and will accompany Francis on this weekend's tour of the Holy Land, claims he has a standing promise from Francis to open the files.

"He undoubtedly feels this is an issue that must be clarified in order to build a sense of mutual confidence that could permit a deeper dialogue between Christians and Jews," Skorka told the Guardian as he prepared to join Francis in Israel.

Four years ago, Skorka and the pope, who was then Buenos Aires archbishop Jorge Bergoglio, co-wrote On Heaven and Earth, a book of dialogues in which Skorka pressed the future Pope hard on the Vatican's files. "What you said about opening the archives relating to the Shoah [Holocaust] seems perfect to me," Bergoglio responded in the book. "They should open them and clarify everything. The objective has to be the truth."

An American historian, Michael Phayer, who is author of The Catholic Church and the Holocaust, believes Pius XII privately shielded some Jews from Nazi persecution, but was unwilling to publicly condemn the Holocaust for fear Hitler would order the bombing of the Vatican.

"The fate of the Jewish people was very low on the Vatican's radar," says Phayer. "Pius XII had concerns, which he considered valid, such as the communist threat, that outranked the Holocaust."

Zuroff, who has dedicated much of his life to tracking down surviving Nazi criminals, would also like access to any Vatican files related to the postwar Nazi fugitives from justice. "We need to know the role of Pope Pius XII and what role senior Vatican officials played, if any, in assisting the escape of prominent Nazi war criminals."

After the war, notorious Nazis such as the Auschwitz doctor Josef Mengele and the Holocaust mastermind Adolf Eichmann were granted safe refuge in Bergoglio's hometown of Buenos Aires, with the aid of the Catholic church.

Zuroff says this might influence any papal decision on the matter. "I think that it could be a factor in finally being able to fully research these questions, although it appears to me that the new Pope's openness and friendship with the Jewish people may be more important ultimately," he says.

Should it choose to open its archives, the Vatican would be following an international trend.

"Since the end of the Cold War many countries, governments and institutions have finally faced the legacies of the second world war and the Holocaust," said Steinacher – a professor at the University of Nebraska-Lincoln.

The USA, Russia, countries from the former communist bloc and the Red Cross itself have opened their sensitive wartime and post-war archives in recent years, said Steinacher. "This is probably the best way to come to terms with the past. A decision by Pope Francis to open the archives for that wartime period would fit into the international trend."

But the historical context should probably be taken into account before accusing Pope Pius XII of knowingly aiding fleeing Nazis. "The understanding of responsibility was very different then," said Steinacher. "People believed that those responsible for the Holocaust were Hitler, Himmler and Goebbels and that others only followed orders. Now we have a completely different understanding of responsibility."