South Korean police said Wednesday they were investigating reports from several major broadcasters and banks that their computer networks had come under a concerted cyber attack.

"Members of our cyber team are investigating this now," a National Police Agency spokesman told AFP.

Yonhap news agency said at least three broadcasters -- KBS, MBC and YTN -- and two banks reported that their computer networks had been paralysed, with the finger of suspicion likely to fall on North Korea.