A new high-quality counterfeit $100 bill has been found in South Korea, bank officials said Tuesday, prompting suggestions the sanctions-hit North might have resumed forging "supernotes".

A team of forgery specialists at KEB Hana Bank have confirmed that a $100 note found at a Seoul branch in November was a fake which was almost impossible to distinguish from real banknotes, they said.

"It was the first of a new kind of supernote ever found in the world," Yi Ho-Joong, head of the KEB Hana Bank's anti-counterfeit centre told AFP.

Previous "supernotes" were dated either 2001 or 2003 but the new forgery is dated 2006.