President Park Geun-hye missed an official dinner in The Hague on Monday and skipped most of her afternoon itinerary on Tuesday due to a cold.
The dinner was hosted by Dutch King Willem-Alexander for world leaders attending the Nuclear Security Summit.
Although Park met with officials according to schedule on Tuesday morning, she missed the afternoon session of the summit as well as a meeting with UN Secretary-General Ban Ki-moon and the closing session of the nuclear summit.
Cheong Wa Dae spokesman Min Kyung-wook said Park "was unable to sleep aboard her plane" while preparing for the summit and "had to handle a tight schedule" since arrival in the Hague. She was put on a drip and rested, he added.
Park also suffered a cold during her visit to the U.S. in May last year, giving rise to concerns that her schedule was too packed.
She arrived in Berlin, Germany on Tuesday after a three-way summit with the leaders of the U.S. and Japan.