The agency said the deceased was in their 90s and living at a nursing home in the southern city of Gwangju. It also stated the person received a second Covid-19 vaccine dose in October.
A total of 21 people in the facility have tested positive for Covid-19 – three of them with the omicron variant – since the first case was reported there on December 24.
South Korea has so far confirmed 1,318 cases of the omicron variant. Experts say it will likely soon replace the Delta variant to become dominant in South Korea.