The 28-year-old agent, identified by her surname Kim, appeared at the Suseo Police Station in southern Seoul Friday for questioning, the Yonhap News Agency reported.
Kim was accused of having posted comments online about main opposition in the country's Dec. 19 election, allegedly using 16 different user IDs to click on and comment on various articles, police said Wednesday.
Police said they found evidence Kim "recommended" or "disapproved of" certain online posts related to the presidential race.
The main opposition Democratic United Party blamed the government for the agent's alleged actions.
Park Geun-hye of the ruling Saenuri Party and winner of the presidential election said the allegations Kim faces violate her human rights.