China on Tuesday rejected a media report that Beijing is planning to build a 1,000-km tunnel to divert the Brahmaputra waters.

"This is untrue. This is a false report," Foreign Ministry spokesperson Hua Chunying said.

"China will continue to attach great importance to the cross-border river cooperation," she added.

According to the Hong Kong-based South China Morning Post, Chinese engineers had submitted to the government a proposal to build a 1,000-km tunnel to carry water from Tibet to Xinjiang.

The newspaper said the tunnel would divert the Yarlung Tsangpo River in southern Tibet to the Taklimakan desert in Xinjiang.

The river downstream is called the Brahmaputra, which joins the Ganges in Bangladesh.

The proposed tunnel, which would drop down from the world's highest plateau in multiple sections connected by waterfalls, would "turn Xinjiang into California", a geotechnical engineer said.