President Rodrigo Duterte's televised remarks on Monday night were among his clearest acknowledgement of the prospects that he could face a deluge of criminal charges for the bloody campaign he launched after taking office in mid-2016.

Nearly 6000 killings of drug suspects have been reported by police but rights watchdogs suspect the death toll is far larger.

"If there's killing there, I'm saying I'm the one ... you can hold me responsible for anything, any death that has occurred in the execution of the drug war," Mr Duterte said.

"If you get killed it's because I'm enraged by drugs," the tough-talking president said.

"If that's what I'm saying, bring me to court to be imprisoned. Fine, I have no problem. If I serve my country by going to jail, gladly."

At least two complaints for crimes against humanity and mass murder in connection with Duterte's campaign are being examined by an International Criminal Court (ICC) prosecutor, who will determine whether there is enough evidence to open a full-scale investigation.

Duterte responded to the complaints by withdrawing the Philippines from the world tribunal two years ago in a move that human rights groups said was a major setback in the country's battle against impunity.

The ICC prosecutor has said the examination into the drug killings would continue despite the Philippine withdrawal.

Duterte has portrayed the drug menace as a national security and public threat like the decades-long communist insurgency that the government is obligated to quell.

"If this is allowed to go on and on and if no decisive action is taken against them, it will endanger the security of the state," he said.

There are 1.6 million drug addicts in the Philippines, Duterte said, citing statistics from an anti-narcotics agency.

Australian Associated Press