The National Agricultural Cooperative Federation, or Nonghyup, faced another problem with its cyber transaction systems early Thursday.

A certain proportion of Nonghyup customers could not access its internet banking system for about five hours until 7 a.m. on the day.

As this marked the fifth glitch in online transactions in less than one year for Nonghyup, its cyber security system has been regarded as seriously vulnerable to hackers.

In April 2011, it suffered a critical breakdown of the network system, which invited a great number of depositors’ worries and financial regulators’ intensive investigation.

While the farm federation-based bank saw similar cases happen last May, December and January 2012, the Financial Supervisory Service has launched a probe into the case again.

In particular, cyber security has emerged as more significant issue for Nonghyup as it is set to launch a financial group in early March. The bank had already made an official apology.

An FSS official stressed that the new financial group is required to raise the level risk management and network systems security.

“Nonghyup suffered a large-scale attack by hackers last year. Gaining confidence via protection of customers should precede the business expansion,” he said.

The newcomer, which will likely be dubbed NH Financial Group, will emerge as the nation’s fifth-largest financial group.

By total assets, the top four groups are Woori Financial, Hana Financial (which ranked second by recently acquiring Korea Exchange Bank), KB Financial and Shinhan Financial.

The other, or smaller, financial groups in the local market include Korea Investment Holdings, BS Financial and DGB Financial.

The first chairman of NH Financial Group is likely to be recommended at a committee this weekend.

By Kim Yon-se (kys@heraldcorp.com)