Water levels of a major river flowing through India's northeast are "normal," an Indian government official said Friday, denying claims a dam in neighbouring China had caused them to plunge.

The senior official in India's Ministry of Water Resources in New Delhi said there had been "no reduction in the flow" of water in the Brahmaputra River which has its source in China's southwestern Tibet region.

The Indian Central Water Commission, which measures the river, has found the levels are "normal," the official told AFP, asking not to be named.

"There have been no sudden changes in the river's flow and there is no need for India to worry or press the panic button," he said.

The official's statements came as China earlier on Friday denied allegations that a dam it was building on the river had affected the lower reaches of the waterway in northeastern India.

"Our projects have not affected the lower stream regions, including those in India," China's foreign ministry spokesman Hong Lei told reporters in Beijing.

China pays attention to the impact on the lower stream regions when developing its water resources, Hong said.

Tako Dabi, a lawmaker in India's Arunachal Pradesh state, triggered concern on Thursday about water levels by claiming that they had dropped and accusing China of diverting the river water on its side.

Likar Angu, chief engineer of the Arunachal Pradesh state water resources department, told AFP on Friday that "one can see a few dry patches" in the Brahmaputra River but the river level was higher than last year.

"This is a lean period and obviously the water discharge is lower, but compared to last year on this day, the water level is 80 centimetres more," Angu said.

The Brahmaputra River is known in China's Tibet region as the Yarlung Tsangpo and it enters India in Arunachal Pradesh, where it it is called the Siang.

The 1,800-mile (2,900-kilometre) river then descends into the plains of adjoining Assam state and ends in Bangladesh in the Bay of Bengal, along the way supplying water to hundreds of millions of farmers and residents.

"To satisfy the needs the Tibet Autonomous Region, China has begun to build the hydroelectric power station of Zangmu in the middle part of Yarlung Tsangpo river," China's spokesman Hong said on Friday.

"It does not have a big capacity and does not retain an excessive amount of water. It will not affect the downstream water regulation and environment."

Beijing has regularly faced complaints over its water usage from Southeast Asian nations for damming the Mekong and Salween rivers, both of which originate in China.