MANILA (UPDATE) - President Rodrigo Duterte's anti-corruption commission said Wednesday it would file charges against some officials of the Philippine Health Insurance Corp. (PhilHealth) before the Office of the Ombudsman following allegations of fraud.

Cases are being prepared against at least 36 "high-ranking and mid-level" officials of the state health insurance firm over violations of the Anti-Graft and Corrupt Practices Act, Presidential Anti-Corruption Commissioner Greco Belgica said.

"We are preparing the cases and are organizing a special team for [it]," Belgica told ABS-CBN News in a phone interview.

• 'Claims without validation': PACC says 36 PhilHealth execs linked to overpayments

Belgica, however, refused to identify the officials who would be charged, adding that the PACC hopes to file "airtight" cases within the month.

"Kakasuhan po lahat yan. Iniimbestigahan namin dito sa PACC, siyempre due process will be observed," Belgica said in a separate interview with Teleradyo.

(We will charge them. The PACC is investigating them and we will ensure that due process will be observed.)

"As we go along, we expect more names to come up," he added.

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The anti-corruption commissioner earlier said the PACC found a "systemic" flaw in PhilHealth involving the firm's IT and legal services that allegedly take advantage of "defects" in the system, allowing fraud to occur.

Belgica said PhilHealth has lost at least P154 billion due to overpayments since 2013. One reason for the overpayments, he said, is that PhilHealth has no system to check the validity of the claims.

The PACC, he said, has submitted its partial report on its investigation on PhilHealth to the Office of the President.

• Anti-corruption body finds cycle of corruption at PhilHealth, identifies officials involved

"Everytime na lang na lumalabas at naiinvolve yung pangalan nila (PhilHealth), lagi na lang naiiskandalo ang buong Pilipinas dahil sa kagrabihan ng kanilang ginagawa," Belgica said.

(Everytime their name is involved, the Philippines is scandalized by the gravity of their actions.)

Aside from the PACC, Congress and the Office of the Special Assistant to the President are also conducting investigations on PhilHealth.

The state health insurer came under fire after its resigned anti-fraud officer, lawyer Thorrsson Montes Keith, went public with allegations of corruption, saying some PhilHealth officials pocketed around P15 billion in funds through various schemes.

He also claimed that several items for the agency's IT department were overpriced by the millions.

• Some PhilHealth execs allegedly pocketed P15B: former anti-fraud official

PhilHealth President Ricardo Morales on Tuesday admitted to lawmakers that his efforts to weed out corruption in the state health insurance firm were not enough.

"Hindi po sapat ang aking ginagawa...Inaamin ko ho, kulang ako sa paghanap ng mga gumagawa ng katiwalian. Marami pa rin sila," he said during a Senate inquiry.

(I'm not doing enough... I admit that my efforts are wanting in weeding out corrupt officials. There are still many of them.)

• 'I am not yet done,' says Morales in ridding PhilHealth of corruption

Morales, who was tasked by President Duterte to rid PhilHealth of corruption, is pushing to overhaul the agency's current information system to curb fraudulent activities.

Duterte's spokesperson Harry Roque on Tuesday said the President would not fire Morales, among retired generals in the administration, unless there is corruption evidence against him.

A Senate hearing on Tuesday revealed Morales even promoted officials already charged for alleged corrupt practices.

• PhilHealth chief justifies promotion of officials tagged in ghost dialysis scam