The Campaign for Helping North Korean in Direct Way scattered some 600,000 leaflets from Yeoncheon, a county bordering North Korea, on Monday evening, local police said.
Lee Min-bok, the head of the group, and his wife participated in the 30-minute leaflet-scattering event, the police said, adding the balloons are believed to have flown in the northeast direction.
The move came after North Korean leader Kim Jong-un said in his New Year message that he is willing to hold summit talks with South Korean President Park Geun-hye if certain conditions are met.
Days earlier, South Korea proposed talks with the North in January to break the stalemate in their relations.
In early October, Lee sent anti-Pyongyang leaflets at the same location, which incited Pyongyang to fire machine gun rounds toward Paju. a South Korean border town about 40 kilometers north of Seoul.
North Korean defectors in South Korea regularly send leaflets to their homeland in a bid to encourage North Koreans to rise up against young leader Kim, drawing fierce protest from Pyongyang.
In November, North Korea ruled out any government-to-government dialogue to mend ties unless South Korea takes action to halt the cross-border leafleting campaign.
South Korea maintains there is no legal basis to prohibit the scattering, calling it a matter of free speech. (Yonhap)