Inland regions outpacing

In contrast, economies in the west such as Chongqing, Guizhou and Qinghai all posted double-digit GDP growth between January and June, helped by policy support. Just last month, Premier Li Keqiang had vowed to sink more cash into the industries and infrastructure in western China.

"Most of Beijing's recent piecemeal pro-growth measures have targeted the central and western provinces," Nie said.

Meanwhile, the biggest export-oriented provinces of Guangdong and Zhejiang saw GDP growth slacken in the first-half of 2014 to between 7 percent and 7.5 percent.

Infographics: China's GDP growth since 1978

Top 10 regions with highest GDP in China

Cooling growth along China's eastern coast is in line with Beijing's goal of cutting its economic reliance on exports in favor of a more sustainable expansion in domestic consumption.

Data earlier this month showed China's economic growth quickened to 7.5 percent in the second quarter, as a raft of stimulus measures helped lift the pace from an 18-month low of 7.4 percent between January and March.

Still, a Reuters poll this month found that China's economy is forecast to grow 7.4 percent this year, the slowest pace in 24 years, and many economists believe more government measures may be needed to maintain its momentum.

In eastern Shandong province, growth edged up to 8.8 percent in the first half from 8.7 percent in the first quarter, but strains are evident from the earlier slowdown in growth, government efforts to reduce excess capacity and a cooling property market.

The amount of bad bank loans in the province surged 25.8 percent between January and June this year, the official Financial News reported last week.

Many economists see the property slowdown as the key risk to national and regional economies this year. A growing number of cities and local governments have eased restrictions on property purchases in recent months to shore up revenues and boost economic activity.