Though mostly counterfeit 100-yuan (US$14) notes are not too hard to make out, people should be careful as cash transactions during Spring Festival are high, it said.

Recent media reports said that 100-yuan notes, starting with numbers "HD90", are fake, but their quality is so high that even cash detectors cannot make them out. The central bank denied the reports yesterday.

On January 2, the Guangzhou-based Information Times reported that a convenience store owner in Dongguan, Guangdong province, received 15 100-yuan notes starting with figures "HD90" and all of them turned out to be fake.