China's courier sector posted steady business expansion in June, official data showed.

The country's courier firms delivered 5.3 billion pieces of parcels last month, up 25.3 percent year on year, according to the State Post Bureau.

This beat Japan's total parcel volume of 4.25 billion in 2017.

Business revenue rose 23.9 percent year-on-year to reach 63 billion yuan (about 9.3 billion U.S. dollars) in June, according to an estimate.

A total of 27.6 billion parcels were delivered during the first half of the year, raking in about 338.46 billion yuan in business revenue.

Partly due to the relocation of industries from the country's developed eastern regions to central regions, the central regions reported robust growth in the courier sector in the first half, with parcel volumes rising 33.8 percent year on year.