Pyongyang is warning the drifting balloons, which look like five-metre long condoms and are inflated with helium, are a deliberate provocation from the South and could lead to war.
The offending balloons are attached to bags filled with 200,000 anti-Pyongyang leaflets and hundreds of DVDs. The bags are also stuffed with $US1 bills: an inducement for nervous North Koreans to pick up the contraband.
With favourable wind conditions, and after a quick chant, South Korean activists release the balloons near the border and then watch them float peacefully into the hermit kingdom.
The balloon launches enrage Kim Jong-il's regime, which likes to starve its downtrodden populace of any information about the outside world.
Rhetoric from the North always remains strong and threatening, as demonstrated by this week's news report from state TV in Pyongyang.
"The North side reminds the South side once again that the army and people of North Korea are compelled to make physical reaction against the South's ceaseless provocative war moves," says the newsreader.
"The North is fully ready for it," she warns
The threats of war are being taken seriously in the South and the man driving the anti-Pyongyang balloon campaign was recently the target of an assassination attempt involving a North Korean agent.
Last week, authorities in the South charged a North Korean man, identified only as An, with trying to assassinate balloon campaign mastermind Park Sang-hak.
Authorities say An arrived in Seoul in the 1990s posing as a defector. Last month he arranged a meeting with Mr Park, whose suspicions led him to notify authorities.
At their rendezvous point, An was found armed with weaponry akin to that of a Bond film.
When prosecutors showed off his arsenal it included a poison dart gun disguised as a torch and a pen equipped with a poison needle.
But if you think his target has gone to ground fearing another attempt on his life, think again.
This week Mr Park was there at the border, as always, filling his giant balloons with helium.