A leading Chinese power company has promised that the world's highest hydropower station in Tibet will not reduce water flows downstream on the Yarlung Zangbo River.

The river, also named Brahmaputra in its lower reaches, joins the Ganges. It traverses China's Tibet, India and Bangladesh before emptying into the Bay of Bengal.

Damming of the river began on Nov 12, marking the formal start of construction of the 7.9-billion-yuan ($1.2-billion) Zangmu Hydropower Station. The move has caused concerns in the countries downstream, including India, who fear the project will disrupt water flows.

"The river will not be stopped during construction," Li Chaoyi, senior engineer of China Huaneng Group, the prime contractor for the project, told China Daily on Thursday.

"After it comes into operation, the river water will flow downstream through water turbines and sluices. So the water volume downstream will not be reduced," he said.

Li said environmental protection has been fully considered in the design and construction of the project, which aims to keep environmental damage to the minimum.

Zangmu Hydropower Station, with six 85,000-kilowatt power-generating units, is a key project in China's ambitious plan to develop Tibet.

The station, with a total installed capacity of 510,000 kW, will ease power shortages in central Tibet and boost regional economic development. The first unit will be put into operation in 2014.

Chen Dongping, general manager of the Tibet Power Generation Co Ltd of China Huaneng Group, said that hydropower is the solution for China's energy saving and emission reduction plan.

The damming of the Yarlung Zangbo River has caused tensions and disputes between China and India, Lou Chunhao, a South Asia studies scholar at the China Institutes of Contemporary International Relations, said on Thursday.

He added China should strengthen cooperation with India on the construction of the hydrological data monitoring system to alleviate India's worries about possible environmental changes.

Conflicts over water have long been highlighted in relations between upstream and downstream countries, and came to the fore again after the drought early this year along the Mekong River, known as the Lancang River in China, he added.

Water resources authorities in China said the falling levels in the Mekong River were mainly caused by a sharp reduction of rainfall in the upper reaches, instead of the impact of upstream Chinese dams as many activists in Thailand, Laos, Vietnam and Cambodia have claimed.

Many environmentalists are concerned about the environmental impacts caused by the construction of the station.

"We are not clear about the environmental impacts of the Zangmu Hydropower Station at present, because the environmental impact assessment report has not been accessible to the public for some reason," said Ma Jun, director of the Institute of Public and Environmental Affairs in Beijing.

Local aquatic animals will definitely be influenced by the station, which changes the water flow speed and waterway, he added.

He said many hydropower stations along the Jinsha River have released their environmental impact assessment reports, so the Zangmu Hydropower Station should as well.