A spokesman blamed miscommunication for the wrong statement being released, Yonhap news agency reported.
A "misunderstanding" had arisen when officials had asked the transition team's office to "advise reporters to use antivirus programs and change passwords often as the press room is vulnerable to outside hacking attempts," said Yoon Chang-jung.
He declined to say if there had been a hacking attempt.
The press room is considered more vulnerable to cyber attacks because the Internet connection there is a commercial network, while the committee uses a more secure government line, Yoon said.
Reporters were asked to use antivirus programs and change passwords often.
The main opposition Democratic United Party charged in a statement the transition team was "out of its mind" for charging that North Korea was involved in hacking the committee. The accusation created the public impression that important information might have been leaked, the UDP said.
South Korean police say they have traced a series of cyber attacks in recent years to North Korea.