"While it is undeniable that most of those who died in the concentration camps were Jews, there were also gypsies, Poles, Italians and Catholics on the list," Tadeusz Pieronek wrote on the website pontifex.roma.it.
"So it is not permissible to appropriate this tragedy for propaganda," he said in the posting, two days ahead of the 65th International Holocaust Remembrance Day.
"There were lots of Poles, but this truth is often ignored today," added Pieronek, 75.
"The Holocaust as such is a Jewish invention," said the former spokesman of Poland's Bishops Conference. The Shoah is "used as a propaganda weapon and to obtain advantages that are often unjustified," he charged.
Pieronek, who was a friend of the late Polish pope John Paul II, added: "You could speak just as forcefully and establish a day of remembrance for the many victims of communism, persecuted Catholics and Christians and so on."
Accusing Jews of "intolerable arrogance," he said they "enjoy good press because they are supported by powerful financial means, enormous power and the unconditional backing of the United States."
Pieronek also criticized Israel for building a separation wall between its territory and the West Bank, which he called "a colossal injustice against the Palestinians, who are treated like animals and whose (basic) rights are violated, to say the least."
Calling for a day honoring the Palestinians, Pieronek lamented that "with the connivance of international lobbies, we don't talk about these things much."
January 27 marks the liberation of the Auschwitz death camp in German-occupied Poland in 1945.
"Of course all this does not deny the shame of the concentration camps and the aberrations of Nazism," Pieronek said.