To solve the water shortage, Hong Kong has been importing water from the Dongjiang River, which runs through southern Jiangxi province into Guangdong province, since 1965, with the full support of the central government.

Currently, the daily consumption of water in Hong Kong is 2.7 million cubic meters.

About 75 percent of the fresh water comes from the Dongjiang, and 25 percent from local reservoirs and rainwater, official data showed.

"With the support of the country, Hong Kong has now achieved a stable water supply," Lee said, adding that there are also potential worries, including climate change and the increasing demand for water in cities along the Dongjiang.

"The plant is very important for Hong Kong's long-term development, so it has won the support of the public," he said, adding that space is reserved next to the first phase of the project for the second stage of construction to expand production capacity.