Auditors have found more accounting problems with projects linked to the Three Gorges Dam, the world's biggest hydropower scheme.

The National Audit Office says some 2-billion yuan remains unaccounted for in connection to an underground hydroelectric plant worth around 7-billion yuan.

The revelation follows a critical report released last year.

It's found numerous problems such as nepotism and embezzlement connected to Three Gorges Dam projects.

The Three Gorges Corporation, which runs the dam, claims all the problems pointed out by the audit have been rectified.

A total of 21 inspections have been conducted by the state audit office since the dam's construction first began in 1994.