Former President Rodrigo Duterte and former police Criminal Investigation and Detection Group (CIDG) officer Royina Garma. ABS-CBN News/file

Former President Rodrigo Duterte has denied the existence of a reward system for police officers who killed drug suspects during his administration's bloody war on drugs.

Former Philippine Charity Sweepstakes Office chief Royina Garma recently bared to the House Quad Committee details related to the reported cash reward system for extrajudicial killings (EJKs) during the Duterte administration.

In her affidavit, Garma disclosed key details about the roles of former President Rodrigo Duterte and Sen. Christopher “Bong” Go in overseeing anti-drug operations.

Garma says Duterte tapped 'Davao Model' on killing drug suspects

She confirmed the assembly of a national task force patterned after the “Davao Model,” which provided police with financial rewards for killing drug suspects, funding for planned operations, and reimbursement for operational expenses.

Quad comm to investigate how alleged drug war 'reward system' was funded

Duterte denied Garma's allegations.

"Walang pulis na papasok na ganon. Makukulong sila. Why would they accept that kind of agreement when it will later on bring their downfall. Walang reward 'yan. Hindi ako nagbibigay ng reward," he said in a Sonshine Media News International (SMNI) program.

Duterte also said he never ordered the police to kill individuals involved in illegal drugs without due cause.

"Ito talaga ang order ko sa kanila. Hanapin mo at arestuhin ninyo kung saan ninyo. Bring them to me, pero pagka-lumaban at nakita ninyo na ang sarili niyong buhay ay mapalagay sa alanganin, patayin ninyo, kasi ayaw kong makita ang pulis ko ang mamatay kaysa sa kriminal," he said.

Duterte also said he is ready to face the investigation panel that probes the alleged summary killings.

Bong Go denies cash reward system in drug war

"I would be happy to appear in both upper and the lower house of Congress," he said.

"And because there are many person scalled or about to be called, baka may ibang tao pang mag-ano. Kung ito lang naman, it's all about me, eh 'di ako na lang. Bakit pa yung ibang tao? ako na mismo ang tawagin nila," he added.

The International Criminal Court is investigating allegations of human rights abuses committed during Duterte's drug war.

Duterte has registered his candidacy on Monday to run for mayor of Davao City in midterm polls due next year.

Davao City is the family stronghold of Duterte, who as president launched a deadly drug war in 2016 that is the subject of local and international investigations.

The House of Representatives is also conducting committee hearings on the drug war killings.

More than 6,000 people were killed in anti-drug operations under Duterte, according to official data released by the Philippines.

ICC prosecutors estimate the death toll at between 12,000 and 30,000. - with reports from Agence France-Presse

Families of summary killing victims pin hopes on ICC