Experts say the measures will facilitate full integration, but they warn of potential pitfalls.

Pan Jiahua, director of the Institute of Urban and Environmental Studies at the Chinese Academy of Social Sciences, says the planners should be wary of creating "monocentric" cities, and should avoid an over-concentration of government departments in Tongzhou to prevent a sharp rise in the local population. He urges planners to consider other parts of the cluster as sites for relocation.

Outside of Beijing, Tianjin and Hebei have also outlined their development plans.

The authorities in Tianjin aim to transform the port city into a base for advanced manufacturing research and development. They also want to see the city become North China's international shipping hub, a mecca for financial innovation and services, and a pilot zone for economic reform.

Ye Tanglin, a researcher in regional integration at the Capital University of Economics and Business, says the developments would be a good fit for Tianjin and would fuel future growth.

Tianjin port is the third largest in China and the fourth largest in the world, which will facilitate the city's ambition to become an international shipping hub, Ye says.

However, he adds that the city must improve its use of neighboring ports, such as Huanghua and Caofeidian in Hebei, not as competitors, but as partners.