BEIJING - Authorities have turned down at least 10 billion yuan ($1.57 billion) in investment because it could harm the environment in a new development zone beside Bohai Bay, a senior official said on Thursday.

Experts and officials have voiced concerns over human activities on the "fragile" sea off the coast of North China's Hebei province, especially after the recent oil leaks.

"The new State-level development zone will be a concentration of green industries," Zhao Yong, deputy governor of Hebei, said at a news conference about the zone that was organized by the State Council Information Office on Thursday.

The State Council approved the development plan on Oct 27, he said, adding that 111 State-owned companies had agreed this past week with the provincial government to form partnerships worth 690 billion yuan. Most of the projects will be in the coastal area.

Zhao said chemicals, equipment manufacturing, steal milling and logistics will be the main industries in the zone. "It will be heavy industry and chemical industries that are supported by high technology, green and recyclable development models," he added.

Administrators in the port city of Caofeidian say they have refused to accept 10 billion yuan in investments that were not "green".

Yet, the development zone, which is being established decades later than those in eastern and southern regions, faces "a grim situation" with environmental protection, said Du Ying, deputy minister of the National Development and Reform Commission.

"Industrial deployment and urbanization will put huge pressure on the marine ecosystem of the 'shallow' and semi-enclosed Bohai Bay", he said.

Sun Baocun, a professor at Tianjin University, said rapid offshore development often ignores the ocean's potential, especially for land reclamation and offshore oil and gas exploration.

Statistics from the State Oceanic Administration showed almost 83 percent of China's coastline has a fragile ecosystem, while coastal areas contribute to 70 percent of the national GDP.

"Considerable amounts of pollutants are still being discharged into rivers flowing into the sea and the risks of potential oil leaks exist," Du said, although he added that he believes "the development of the zone will not have a major impact on the bay".

Hebei deputy governor Zhao said his government is trying to integrate public services such as social warfare, medical insurance and pension systems with the province's two neighboring municipalities, Beijing and Tianjin.