The authorities have held a series of meetings of "inminban," or people's squads, the most basic North Korean administrative unit, typically composed of 20 to 40 households for surveillance of each other, to identify those possessing handsets.
Those reported to have cell phones or other smuggled electronic devices were urged to surrender them to police, the group said, citing its sources "inside North Korea."
The authorities warned that those who did not surrender the devices would face punishment and said authorities were using special devices to track cell phone use, the Intellectuals Solidarity said.
Police has promised to punish "those spreading capitalist ideas and eroding socialism," the group quoted one of the sources as saying.
Many North Korean border traders are using smuggled mobile phones, making use of Chinese cell phone networks. The smuggled mobile phones typically use pre-paid cards.
Chinese communication firms, which have rapidly expanded their cell phone services, have installed relay stations along the border with North Korea.
Cell phones have become more essential to North Korean merchants conducting business along the border after the regime tightened border controls. Some have made cell phone calls to their relatives in South Korea to ask money.