The government plans to offer a smartphone application from early May that will warn users if they have been in contact with someone diagnosed with the new coronavirus, raising concerns about user privacy.

The system, based on a contact-tracing app developed by the Singaporean government, will detect and record nearby phones that have the app installed. When one of the users is diagnosed as infected with the coronavirus, an alert message will be sent to those who have been in close contact.

"It is an extremely effective way" to prevent the spread of the disease," information technology policy minister Naokazu Takemoto told a recent news conference, adding steps are needed to ensure that user privacy is protected and public health centers are involved.