"The problem cannot be solved quickly," she said.

It is online retailers' top priority to make sure that consumers, either in lower-tier or large cities, get the same quality services, industry insiders said.

Many e-commerce players already have tried to improve the "weak link".

Alibaba signed an agreement with State-owned China Post Group Corp in June to boost its presence in rural areas. China Post has the most extensive delivery networks in lower-tier cities, especially in villages.

JD is catching up in this sector. At the beginning of the year, it launched a "pioneer station" program to encourage its deliverymen to go to their hometowns and expand delivery networks there.

"A sizable proportion of our 20,000 deliverymen are from lower-tier cities. Encouraging them to go back there to establish delivery stations is a win-win strategy for both them and JD," said Shen of JD, adding that as many as 135 new delivery stations have been built through this program.

JD.com prices IPO above expectations	Top 10 Chinese Internet firms eyeing IPOs in US