MANILA - An expert on information technology believes the glitch that affected customers of the Bank of the Philippine Islands (BPI) is more of an internal systems error than an incident of hacking.

Possible proof of this, IT expert Lito Averia said, is the fact that while some customers reported negative balance in their accounts, there were also some who reported being "instant billionaires" because of the glitch.

"Base sa news reports na nakikita natin, meron ding accounts na nag-double credit naman. Ibig sabihin, nadagdagan 'yung pera mo. E may hacker ba namang magdadag ng pera sa account mo?" he told DZMM on Thursday.

Despite this, Averia said BPI should still do an in-depth investigation on the incident in order to identify what particularly went wrong in the bank's systems and to come up with improvements on these areas.

He explained that ATM networks are separate from the bank's main system. This means records of each ATM transaction are being regularly used to update the accounts on the bank's main system.

The error, said Averia, could either be entirely on the system, if the process of updating of transaction is automatic, or human, if the process is manual with actual bank personnel logging in and doing the updates.

"Kung manual, halimbawa, ang pagkaka-update... Bago ka pumasok sa sistema kailangang mag-log in ka rin. May username, password ka ring gagamitin para ma-access mo ang sistema at magawa ang kaukulang trabaho. At yan ay may record rin. So kung may human intervention 'yan at nagkamali, matutukoy kaagad 'yan," he explained.

Averia said no system is 100% safe from hacking but there are ways for companies to beef up their protection. For bank customers, he said, vigilance should be observed

The IT expert said it will be very helpful for customers to check their balance before and after an ATM transaction to make sure their money is intact.

He added that bank customers should not throw away receipts after an ATM transaction as these records would be handy in cases glitch or a hacking.