Service disruptions, some of which continued into Sunday, hit some of the country's most-used apps and websites, including Kakao messenger and the company's online payment, gaming and music streaming services.
read moreThe outages highlighted how reliant South Korea is on Kakao messenger, which is the default form of communication for many government and business services.
Register now for FREE unlimited access to Reuters.com Register"We ask that government ministries also make every effort to ensure that Kakao and others can responsibly and promptly restore services," Yoon said, according to his spokeswoman.
Yoon ordered the science and ICT minister to provide personal support, and called for an investigation to identify the exact causes behind the incident.
Register now for FREE unlimited access to Reuters.com RegisterReporting by Josh Smith; Editing by Tom HogueOur Standards: The Thomson Reuters Trust Principles.