Japan's financial watchdog says that some of Japan's cryptocurrency exchange operators are about to be slapped with punitive measures by the Financial Services Agency.

The Financial Services Agency has been inspecting the exchanges since hackers made off with 58 billion yen ($550 million) worth of NEM coins from Coincheck, a popular exchange based in Tokyo. According to Nikkei, the FSA will send business suspension orders to an unspecified number of cryptocurrency exchange operators.

The penalties follow the uncovering of flaws in customer protection and anti-money laundering measures during on-site checks at the exchanges, the Nikkei said.

In addition, the FSA is set to issue a second business improvement order to Coincheck. The agency will monitor any progress the operator makes toward compensating its clients for losses.

Coincheck suspended its operations the day it was hacked. It has since returned any yen its customers were holding with it but has not reimbursed its clients for their cryptocurrency holdings.

Last year, Japan became the world's first country to regulate cryptocurrency exchanges at the national level.

Many global regulators have warned about cryptocurrencies this year and China has banned financial institutions from processing them.