BEIJING (BLOOMBERG) - China's central bank has denied a rumour that a detained senior official forged US$314 billion (S$428.89 billion) worth of banknotes.

Chen Yaoming was one of the people in charge of minting China's cash until he was detained recently on suspicion of unspecified "serious crimes".

His detention was one of the top trending topics on Weibo on Wednesday (Dec 22), with some people speculating that it was because he had been printing banknotes with the same serial numbers as other notes.

The rumour that he'd printed 2 trillion yuan (US$314 billion) worth of such notes is false, the People's Bank of China said in a statement on Wednesday, and has been reported to the police.

The printing of renminbi notes follows a strict process and has always been carried out in accordance with laws and regulations, the PBOC said.

However, there was no explanation of why Chen was detained, either in the central bank's statement or in the notice from the anti-corruption watchdog earlier this month, which said that he'd surrendered himself and was under investigation.

Forging two trillion yuan in banknotes would be a truly mammoth undertaking - the largest note in China is 100 yuan, so two trillion yuan would be 20 billion notes, and would be worth about 2 per cent of China's 2020's gross domestic product.