TOKYO — The Financial Services Agency will expand its on-site inspections to 15 other virtual currency exchanges operating pending formal registration to check their risk management systems, a minister said Friday.

The planned inspections follow one that the watchdog launched in early February on Coincheck Inc., which lost digital money worth 58 billion yen ($540 million) at the time to hackers last month.

“We have decided to conduct on-site inspections on 15 operators that are awaiting approval after examining their reports (on risk management systems),” Financial Services Minister Taro Aso told reporters after a Cabinet meeting.

Aso said the FSA notified five of the 15 operators Wednesday of its plan, adding the inspections are “designed to make sure customer protection is ensured.”

Virtual currency exchange operators are legally required to register with the government. There are 16 registered operators and another 16, including Coincheck, which are awaiting approval.

The largest-ever virtual currency theft from Coincheck came amid growing debate about whether to regulate them.

Coincheck submitted a business improvement plan to the FSA earlier this week, pledging to improve its security system. It has pledged to reimburse around 260,000 holders of NEM coins to the tune of 46 billion yen but has not said how it will do so.