The Vatican's newspaper announced the plan, saying it will "render service to the historic truth," and officials said Tuesday the material will be accessible soon.
However a panel of Jewish and Catholic scholars who examined the 11 volumes of material a decade ago concluded that more information was required to decide whether Pius did everything he could to head off the Nazis' efforts to exterminate European Jews.
Some Jews and others contend Pius should have done more, and are angered by.
The Vatican's daily newspaper L'Osservatore Romano said Gary Krup, an American who heads the Pave the Way Foundation, which seeks to strengthen Catholic-Jewish relations, was behind the online initiative. It quoted him as saying that the Pius XII papacy "has become a source of friction."
Benedict sparked renewed outrage among Jewish groups in December when he signed a decree on Pius' heroic virtues, paving the way for him to be beatified once a miracle attributed to his intercession is confirmed.
During a visit to Rome's main synagogue last month, Benedict didn't mention Pius by name but said the Vatican "itself provided assistance, often in a hidden and discreet way" to Jews during the war. Benedict said Catholics acted courageously to save Jews during World War II.
The panel of Catholic and Jewish scholars that examined the material said it suspended its work because the Vatican had not released all of its archives from the World War II years.
The Vatican has said those archives won't be catalogued and ready until 2014 at the earliest.
By Associated Press Writer Victor L. Simpson