Japanese government officials have asked the operator of the Line messaging app to explain how it will do a better job of protecting user data.

Line revealed in March that a Chinese firm it had contracted to perform system maintenance had access to user details. It also acknowledged it had been storing the personal information of users in South Korea.

A government investigation found engineers at the Chinese firm had accessed sensitive data 132 times.

But the probe did not uncover evidence of leaks or privacy violations.

Government officials concluded that neither Line's data management nor its explanations were good enough.

They have issued the firm with an administrative guidance order. That means Line will have to report back on the measures it will take to prevent a recurrence.