BEIJING - The National Audit Office (NAO) said Tuesday it has uncovered 3.37 billion yuan ($530 million) in arbitrary fees to enterprises so far amid the country's efforts to simplify business registration.

A total of 367 million yuan in arbitrary charges have been found at 20 quality supervision stations nationwide since 2012, and some industries in Guangxi Zhuang autonomous region were found to have levied over one billion yuan in arbitrary fees, said Zhou Shuda, a senior NAO auditor, during a working conference.

During the probe, the NAO found many cases in which central departments failed to adequately streamline administrative processes, and some financial institutions raised financing fees for medium and small enterprises, he said.

Zhou said the NAO will strengthen audit supervision in the future and urge departments involved to stop the arbitrary charges.

Since 2014, a crackdown on arbitrary charges has helped businesses save 30 billion yuan, according to the State Council.