The number of parcels Japan Post delivered between last April and early this month has reached a record 184.97 million, according to the governmental postal service agency.
The previous record was set in the 12-month period beginning April 1, 1970, Japan Post said.
The new all-time high was logged partly because the public postal service teamed up in November with the major convenience store chain Lawson Inc. to provide Yu-Pack, a door-to-door parcel delivery service.
The growth of Japan Post's parcel service could draw flak from archrival Yamato Transport Co., a private parcel delivery firm, industry analysts say.
Yamato has blasted Japan Post for squeezing its profitability and that of other private-sector service providers.
"Our market share fell to 6 percent from the 71 percent clinched by the then Posts and Telecommunications Ministry in fiscal 1970, because the market has since ballooned," Japan Post President Masaharu Ikuta said during a news conference Wednesday. "We would like to recoup ground in the coming years to the point of seizing a 10 percent share," he said.
Last October, Japan Post adopted a system for determining delivery charges based on parcel size instead of weight.
It also began offering customers a new door-to-door delivery service for handing larger packages, including golf bags and snowboards.
Under the Yu-Pack service, Japan Post delivers parcels when users bring them to a post office, or users can opt to have mail carriers show up at their homes to collect parcels for delivery.
Convenience store chains that have formed tieups with Japan Post are providing increasingly crucial support because they offer round-the-clock operations.