North Korea has apparently told South Korean businesses in the joint Kaesong Industrial Complex to stop handing out Choco Pie snacks to the North Korean workers there.

The marshmallow-filled snacks are so popular and fetch such high black-market prices that they have become a kind of unofficial currency in the area.

Since the complex was launched in 2004, Choco Pies have become the most popular South Korean product not just among workers at Kaesong but in the entire Stalinist country.

Many workers take their quota of the snacks home to share with their impoverished families and friends or to sell them.

According to South Koreans factory staff, North Korean apparatchiks demanded a halt to the supply of the sweet snacks last month. Now businesses give worker sausages, instant noodles, powdered coffee, cold noodles or chocolate bars instead. Some even wanted to be paid in U.S. dollars.

Until then the South Korean businesses gave their North Korean workers around a dozen Choco Pies a day as a treat for overtime work. They have reportedly been a great morale booster.

A Unification Ministry official said the North Korean workers told their employers that they were fed up with Choco pies and wanted something else. But in reality Pyongyang appears concerned about the impact the snacks have had on the North Korean public as the products inundate open-air markets, not least because they are a kind of practical pro-South Korean propaganda.