Both Samsung and Apple are exchanging or offering free servicing of faulty smartphones.
Samsung on Sunday said some of the cameras of its latest Galaxy S5 smartphones malfunctioned. The defective phones show the message "warning: camera faile" when the camera is turned on, and no pictures can be taken.
The defect was first found among Galaxy S5s sold by Verizon, the U.S.' largest telecom.
Samsung said "a limited number" of early production batches have the defect, but the problem "has been rectified since."
Consumers in Korea who bought a Galaxy S5 up to two weeks ago can get a replacement from the store they bought it from. If they have had it for longer, they can get a free repair from a Samsung Service Center.
Meanwhile, Apple on Friday said some iPhone 5s made in 2012 and 2013 have malfunctioning power buttons. The company will repair them for free.
Korean customers can get a free repair from May 2.