Some South Korean citizens, including numerous North Korean defectors, have been practicing leafleting exercises flying giant helium balloons for years, which enrage Pyongyang that has threatened military strikes in response.
In October 2014, North Korean frontier guards attempted to shoot down a set of balloons, triggering a brief exchange of fire across the border.
Defector-turned-activist Park Sang-hak declared the planned launch would take place on March 26 at Imjingak, a park located in the border city of Paju which is very close to North Korean boundary.
"We will fly 10 million propaganda leaflets criticising Kim Jong-un's severe violation of human rights," Park said in a statement.
The planned event will coincide with Saturday’s anniversary of the sinking of a South Korean warship in 2010, resulting in the loss of 46 sailors. Seoul continuously blamed North Korea as a perpetrator and imposed unilateral trade and investment sanctions on Pyongyang in response.
The South Korean government says the activists have a right to carry out leaflet launches, although it has, in the past, used police to block such exercises during moments of heightened inter-Korean tension.
The Korean peninsula is the scene of profound tensions in recent weeks between North and South Korea due to North’s nuclear tests and several missiles launches, and South’s military drill collaborated with United States.
The Unification Ministry, a South Korean body established to promote inter-Korean dialogues and exchanges, warned that officials would have to consider whether a leaflet launch in the present atmosphere might trigger a North Korean response that would "threaten the lives and property of our citizens".
The peninsula was divided into two parts following World War II by United States and former Soviet Union with the national division and separate governments, which eventually led to Korean War during 1950-53 and caused so far permanent tensions in the peninsula.
Following North Korea's fourth nuclear test on January 6, South Korea resumed blasting a mix of K-pop and propaganda messages into the North, using giant banks of speakers on the heavily militarised border.
North Korea has responded by dropping its own leaflets over the border, attacking South Korean President Park Geun-hye.