Philippine President Rodrigo Duterte on Thursday said he was willing to face the music for his war on drugs and a complaint filed with the International Criminal Court would not stop him pursuing his bloody campaign.

The former prosecutor said he was man who was true to his word, including wiping out drugs, so he would accept the consequences, even if it meant prison, or death.

"I will continue my campaign ... I just stood by with my promise, all other politicians they pay lip service to the problem," he told reporters.

"You want to try to do everything to put me in prison, please go ahead ... if it is my destiny to go to jail then I will go to jail, if somebody will kill me for killing the idiot drug people, so be it, I die."

Thousands of Filipinos have been killed since Duterte unleashed his ferocious campaign nearly 10 months ago. Police say they have killed only in self-defence, and the deaths of other drug dealers and users was down to vigilantes or narcotics gangs silencing potential witnesses.

Human rights groups say official accounts are implausible and accuse Duterte of supporting a campaign of systematic extrajudicial killings by police. The government denies that.

A Philippine lawyer filed a complaint at the ICC on Monday against Duterte and senior officials of mass murder. The 77-page filing said Duterte "repeatedly, unchangingly and continuously" committed crimes against humanity.

The complaint is the first publicly known communication to the ICC against the president and is based on the testimony of two self-confessed hit men who said they had worked under Duterte when he was a mayor, statements from rights groups and media reports, including a Reuters series on the killings.

Duterte stood by police, and said he had never given an order to commit murder, but to defend themselves if their lives were at risk.

He dismissed questions about police carrying out extrajudicial killings and appeared to blame criminals for thousands of deaths at the hands of mystery gunmen.

"Of course, who else?" he said.

Duterte also dismissed an editorial in the New York Times on Tuesday that said the ICC should promptly open an investigation into the drugs war. It described Duterte as "a man who must be stopped."

Duterte said it was the newspaper that should be stopped.

"New York Times, assholes, they are assholes," he said.