Several dozen South Korean activists launched balloons carrying anti-Pyongyang leaflets, condoms and sanitary pads across the border with North Korea on Thursday.
The launch went ahead despite a recent threat from Pyongyang of military strikes against similar propaganda exercises by North Korean defectors.
Activists used 20 gas-filled balloons to float packages containing 150,000 leaflets and 5,000 condoms across the western part of the border in Yeoncheon County.
"We've heard condoms are particularly difficult to secure in the North," said Bong Tae-Hong, who heads the right-wing activist group Right Korea.
"North Koreans also need them as contraceptives and for protection against sexually transferred diseases," Bong told AFP.
Also included in the packages were sanitary pads, electric torches, sweets, underwear, socks and toothpaste.
South Korean police blocked a similar leafleting exercise last month by a group of North Korean defectors, after Pyongyang said it would respond with a "merciless" military attack.
The balloon launches take place regularly and are usually carried out by three distinct groups -- North Korean defectors, Christian activists and right-wing organisations.