Conservative Catholic priest Floriano Abrahamowicz said Thursday that "the only thing certain" about the gas chambers "was that they were used for disinfection."
Another priest who denied the Holocaust altogether was rehabilitated by the pope.
Abrahamowicz, of Treviso in northern Italy, was quoted by the Tribuna di Treviso on Thursday in a report that received worldwide coverage due to the pope's recent rehabilitation of a bishop who denied the Holocaust, sparking a battle between the Vatican and the Chief Rabbinate of Israel.
Abrahamowicz is a traditionalist like British-born Richard Williamson, whose excommunication was lifted by Pope Benedict on Saturday along with three other bishops after 20 years of exile.
The Treviso priest said he could not say for sure that people were murdered in the gas chambers because he had not investigated the claim.
He said he did not doubt six million Jews were killed in the Holocaust, but compared the Nazi murder of the Jews to "other genocides" that did not receive similar publicity, including Israel's military offensive in the Gaza Strip and the allies' bombing of German cities during WWII.
He denied that he and other conservatives were anti-Semites, and stressed that his father was a Jew. However he described the Jewish people as slayers of God, and called on the Jews to "adopt our lord Jesus".