Companies that have their clients' personal information leaked would be subject to a fine of up to 500 million won ($466,000) under a proposal being pushed by the Ministry of Security and Public Administration (MOSPA).
The ministry will announce its plan today to revise the relevant law, which will have to win approval of the National Assembly before going into effect.
The measure came after a series of recent large-scale data thefts which prompted concerns that financial scammers may take advantage of them.
"Private companies are required to step up security in managing people's resident registration numbers via an enhanced sense of responsibility and better technology," an MOSPA official said. "We will also double efforts to prevent recurrence of data leaks, which caused grave concerns to people."
In January, a credit ratings agency employee was found to have stolen personal data of tens of millions of credit card users, which included resident registration numbers, bank accounts and credit ratings.
Regulators and the three card issuers ― KB Kookmin Card, NH Nonghyup Card and Lotte Card ― claim that the leak was contained, but skepticism still lingers.
In addition, hackers are found to have compromised the website of the country's No. 2 wireless operator to steal the personal information en masse from 9.81 million customers.
New KT Chairman Hwang Chang-gyu had to apologize for the mishaps, which led to calls for the country to phase in a new system that is less vulnerable to outside threats.
In particular, privacy advocates claim that the resident registration numbers hold too much personal data ― the 13-digit system is a combination of birth date, gender, first registration region and registration order.
They contend that the personal data-filled number might lead to identity theft, a fast-growing crime in the digital age of today, if it ends up on the hands of unscrupulous people.
The government has tried to usher in a new online identification system to substitute for the resident registration numbers, but such attempts have failed to achieve tangible results thus far.