Four workers in a "ghost-money" factory in Huilai county of Guangdong province, suspected of making fake banknotes, have been charged with counterfeiting offences by the local court two months after police discovered the factory.

The fake bank notes represented 80 million yuan ($ 12.5 million) at face value.

One of the suspects, identified by the authorities as Shi, is a former employee at a printing factory. After more than 10 years working in printing, Shi discovered a unique way to forge currency.

According to Shi, it took the counterfeiters only 7 to 10 days to make the fake banknotes. Shi and his partners disguised the factory by covering the walls and roof of the room with blankets and building materials to control the noises.

Police said they discovered the factory's location a week before the counterfeit banknotes were forged.