The Cabinet on March 6 approved legal revisions designed to prevent major telecommunications service providers from grabbing all available numbers for mobile phones and adding to their huge surplus of idle numbers.

The new system under the revised Telecommunications Business Law is expected to start in fiscal 2019, and it will force the carriers to “return” to the government all phone numbers that are not expected to be assigned to users for a few years.

Traditionally, the Ministry of Internal Affairs and Communications has allotted 10 million to 15 million mobile phone numbers to three major telecommunication providers, including NTT Docomo Inc., every year upon their request.

The ministry now faces a shortage of available phone numbers, but it found that 29.7 percent of all numbers it has allotted remain unused and are simply being held in the possession of the service providers.

“The government is running out of phone numbers to allot, but there are many unused numbers,” said Seiko Noda, the telecommunications minister. “The new system will sort out the disproportion.”

The ministry has already run out of numbers starting with “090” and “080.” And it had only 25.9 million numbers left starting with “070” as of March 2017.

However, the companies have yet to assign 72.4 million numbers to phone users.

Under the revised law, the telecommunication businesses must draw up estimates on how many phone numbers they need for both landline and mobile phones. Any surplus numbers they will not use in a few years must be returned to the government.

If they fail to reach their estimates, the ministry will demand they return additional numbers. If the companies refuse, they face a maximum fine of 2 million yen ($18,800).