The Lower Russei Chrum River hydroelectric dam, which is the Cambodia's largest hydropower plant, has begun testing operation after it has been constructed for three and a half years, a company's official said Saturday.

The 338-megawatt hydropower dam, situated in the jungle in Mondol Sima district of southwestern Koh Kong province, was developed by the giant power company China Huadian Corp for a cost of 500 million US dollars under a 35-year build-operate-transfer contract.

Under terms of the agreement, the plant sells power to the state-owned Electricity of Cambodia.

Le Jianhua, deputy general manager of China Huadian Lower Russei Chrum River Hydroelectric Project Company, said the firm has completed the construction of the dam nine months earlier than the schedule.

He said the dam has two reservoirs and four generators.

"We have tested the operation since December last year. Up to now, the plant has supplied 190 million kwh to the Electricity of Cambodia," he told reporters, adding that the dam is capable to generate the power of 1 billion kwh per year.

"It is the first-ever largest hydroelectric plant in Cambodia at the moment," he said.

Cambodia has a serious shortage of power facilities. Only about 35 percent of its households have access to reliable electricity, according to the Ministry of Mines and Energy.

"The operation of the dam will contribute to developing economic activities and further reduce electricity shortage in Cambodia," Le Jianhua said.

China is the largest investor in building hydroelectric dams in this Southeast Asian nation. According to the Ministry of Mines and Energy, Chinese companies have invested over 1.6 billion US dollars to construct six hydroelectric dams with the total capacity of 928 megawatts in Cambodia.

To date, four dams have come into operations, and the remaining two dams are expected to be completed the construction by next year.