Photo/Illutration A mailbox of Japan Post Co. (Toshio Tada)

Mail delivery is likely to be less speedy and only available on weekdays as part of efforts to improve the earnings of Japan Post Group companies, including Japan Post Co.

The internal affairs ministry will submit a bill to revise the Postal Law at an extraordinary Diet session to be convened late this month to authorize the termination of Saturday mail services.

Submission of the bill was postponed due to a scandal involving shady sales of policies of Japan Post Insurance Co., another Japan Post Group company.

If the bill passes, mail delivery on Saturday will, in principle, end in the fall of next year at the earliest, meaning no mail will be delivered on weekends.

The change will ease the burden on delivery staff and employees sorting the mail and reduce costs by more than 60 billion yen ($570 million) annually, sources said.

Under the proposed revisions to the Postal Law, the period from posting mail to delivery will also be changed from “within three days” to “within four days.” That means mail posted on Thursday will no longer be delivered on Friday or Saturday but the following Monday.

Japan Post also plans to end next-day delivery, in principle. It will continue its express mail delivery service on Saturday and consider lowering the fee for the service to minimize a possible backlash from customers against the anticipated decline in the quality of the nation's mail service.

The Japan Post Group, which was incorporated in 2007, is still in the process of privatization.