What is the time limit for replying to official actions in Korea?

Two months. The applicant may however request up to four one-month extensions, subject to payment of an additional fee each time. Furthermore, the KIPO Commissioner and the President of the Intellectual Property Tribunal (IPT) may (on request or ex officio) extend the period for submitting a request for a trial by up to 30 days, or even longer in exceptional cases such as applicants living in inaccessible areas.