President Rodrigo Duterte castigated on Monday Ombudsman Conchita Carpio Morales, telling her to shut up after she accused him of "goading" people to kill drug addicts.

In a speech during the mass oath taking of newly appointed government officials, Duterte challenged Morales to cite a law he is violating whenever he threatens criminals to death.

"Ombudsman Morales, find me a law which says I cannot threaten criminals with death. Find me a law which would bar me from saying, 'I will destroy you if you destroy my country.' Because if you can do that, I will step down tomorrow, just give it to me," Duterte said.

"Fix the Ombudsman, you think you are saints there? Do not play God and shut up," he stressed, citing there was also corruption in the Office of the Ombudsman.

Duterte became irked with Morales when in an interview recently with Japan's NHK World, she has said that the President was goading people to kill drug suspects.

Morales is the aunt of Duterte's son-in-law, lawyer Mans Carpio, husband of Davao City Mayor Sara Duterte.

Duterte said Carpio should not act like a "hero" because he was just trying to solve the drug problem in the country.

"Don't act like a hero just like what others were trying to portray. I'm already having a hard time here, yet you still want to be like Obama," he said.

Duterte previously slammed former President Barack Obama who also raised concern over the increasing number of individuals being killed for their alleged involvement in illegal drugs.

He had called Obama "son of a whore."

Thousands of people, who were allegedly involved in illegal drugs, have been killed since Duterte assumed office last year. Celerina Monte/DMS