The first flight from Dubai is due to touch down in Phnom Penh on Saturday evening after a brief stopover in Yangon, Myanmar’s former capital.
Sin Chanpeourozet, a young female CNRP activist, was one of seven opposition councilors elected in the commune.
It went on to threaten legal action against the CNRP for “slander or false statement”.
The $2.3 billion project will be located about 1,500 kilometers from the Cambodia-Laos border and is expected to be completed in 2024.
Analysts said the comments were an attempt to gain support ahead of a general election next year.
Phouk Prathna, 25, is one of the youngest local councilors elected to run a local authority in Bavet commune, Svay Rieng province.
The Situation Room, a group comprising several election monitoring NGOs, said the CPP had spent some $15,000 on average campaigning in each commune.
Cambodia generates about half of its electricity from hydropower, while it imports significant amounts from Thailand, Vietnam and Laos.
The National Election Committee (NEC) said the CPP had secured 1,156 seats out of a possible 1,646 and more than 3.5 million votes.
Final results confirm dominance of Prime Minister Hun Sen's ruling party, but strong showing by opposition saw its prospects boosted for next year's general election.
In fact, as the number of people killed in land conflicts around the world soars, more than half of the dead have been women, rights watchdogs say.
The result will be announced at 9am and again at 7pm, according to the NEC’s website.