A man passes by the Shinhan Bank, in Seoul, South Korea, March 20, 2013. South Korea's computer networks of the main broadcasters and banks were completely paralyzed on Wednesday. (Xinhua/Yang Qilin)

South Korea's financial watchdog said Wednesday that it is seeking to find reasons for the abrupt paralysis of computer networks at banks. "Computer networks at Shinhan Bank were completed stopped at around 2:15 p.m.,"a senior official in charge of IT network supervision at the Financial Supervisory Service (FSS) told reporters at an emergency briefing.

Automated teller machine (ATM) and computers used by officials at branches of Jeju Bank and Nonghyup Bank were also halted, the official said, adding that life and non-life insurance units of Nonghyup spotted computer files of some officials deleted.

The financial watchdog has yet to find the reason for the network paralysis, the official said, noting that it would try all- out to prevent bank customers from being damaged.

The comments came after local media reported that computer networks of major broadcasters, including KBS, MBC and YTN, and some banks were paralyzed simultaneously. The National Policy Agency (NPA) said it is reviewing all possibilities, including cyber attack.

South Korea's presidential Blue House also started to investigate the reason of networks paralysis.