MANILA - Health Secretary Francisco Duque III said he is open to an investigation on the allegations that there are "mafia-like operations" inside the agency.

The allegation was made by Dr. Francis Cruz, a former Health Department consultant, who bared names of past and present officials who supposedly benefited from the controversial P3.5-billion government dengue vaccine program.

According to Duque, once Cruz is able to present documents to prove his claims, he will not hesitate to open up a probe. He also said he will not stop Cruz from filing a complaint if he believes he has enough evidence.

Among the current officials accused by Cruz are Dr. Mario Villaverde, Dr. Gerardo Bayugo, Lilibeth David, Carol Taño, Lyndon Lee-Suy, Nestor Santiago, Joyce Ducusin, Marwin Bello, Leonila Gorgolon, Ariel Valencia, Rio Magpantay, and Julius Lecciones.

Cruz also mentioned former Health Secretary Janette Garin and undersecretaries Nemesio Gako, Kenneth Hartigan-Go, and director Yolanda Oliveros as part of the alleged "mafia" that allowed for the purchase of French-made dengue vaccine Dengvaxia.

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The Health Secretary said he was able to talk to some of the accused officials as some of them were appointed under the Duterte administration. He said the DOH will review the contracts of the said officials.

Cruz told DZMM Monday that he had already submitted his evidence to the Volunteers Against Crime and Corruption last May 2017, and also to the Senate. He said the VACC is preparing to file charges against the DOH officials.

"Nakaharap na sa inyo yung pruweba nag-a-attend ka na ng Senate hearings... Don't look for me, it's staring at you, Secretary. Napakatino mong tao. Just be brave," Cruz said, calling on Duque.

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--with a report by Kori Quintos, ABS-CBN News