The government announced a set of measures on Wednesday designed to prevent future leaks and minimize the damage to clients if a leak does occur.
In the midst of growing public anxiety about the possible financial crimes that could be committed using the stolen data -- which includes bank account, credit card numbers and personal credit records -- financial firms will now be barred from collecting an excessive amount of personal data from customers.
The government will also strengthen the punishment on institutions that use client data for their marketing activities.
"Financial institutions will be prohibited from using client data for marketing purposes and the CEOs of the financial firms in question will be subject to strong punishments."
Firms that are found to have used client data for marketing could be fined up to one percent of their sales in the event of a data breach.
"The government will fine banks and credit card firms up to 4.6 million U.S. dollars if they are found to have mismanaged personal data and client data will be automatically discarded five years after a client's final transaction."
The government also plans to impose heavy fines on the three card firms - KB Kookmin, NongHyup and Lotte - that had data stolen from their internal servers.
And at the press conference Wednesday, the chairman of Korea's financial watchdog offered to take full responsibility for the data breach.
"We apologize for the data leak that inconvenienced the people. We will do our best to wrap the case up quickly and promise to prevent such mishaps in the future."
"The government has rolled out its strongest ever measures to raise the severity of personal data theft, and with comprehensive probes to kick-off soon, the government hopes to prevent similar cases from happening again in the future.
Ji Myung-kil, Arirang News."