President Rodrigo Duterte castigated the Catholic Church anew on Tuesday as he even offered to resign if the "filthiness" he has been accusing the bishops of is not true.

But if his allegations were true, all prelates should quit, Duterte said in a speech in Malacanang where he met families of the slain police commandos in Mamasapano, Maguindanao on January 25, 2015.

"We have the same filthiness," except that the prelates, aside from being womanizers, were also corrupt, he said.

Duterte said he is not corrupt, but he is a womanizer.

"I challenge you (Catholic) Bishops Conference (of the Philippines), let us all resign tomorrow, simultaneously, ok? I will deliver my resignation on bended knees. I will put it on Rizal (monument) in Luneta," said Duterte as he showed a book entitled, "Altar of Secrets" written by late Aries Rufo, a veteran reporter.

"I challenge you now, I challenge the Catholic Church. You are full of shit," Duterte said as he recalled the Pajero given by then President Gloria Macapagal-Arroyo to some bishops.

He also vowed to write a book about the "hypocrisy" of the prelates, recalling his experience in the hands of the priests when he was still studying in Ateneo de Davao when he was still in high school.

Duterte has been irked with the Catholic Church for criticizing the alleged extrajudicial killings of individuals who were allegedly involved in illegal drugs amid the government's campaign against illegal drugs. Celerina Monte/DMS