Hun Sen's Facebook, which how has 1.2 million "likes", carries images and videos of new infrastructure and credits him with Cambodia's speedy economic development.
Some of the 63-year-old's most recent activities were sharing links to what he says are his favorite TV shows, "Cambodian Idol" and "The Voice" - local spin-offs of hit U.S. talent contests.
In June, Sen's government held two mandatory classes for 400 heads of Phnom Penh schools, which included showing them how to get Facebook accounts and write supportive messages for the ruling Cambodian People's Party (CPP), according to people who attended the sessions.
Government spokesman Phay Siphan said the classes were part of a broader exercise to train civil servants across the country to use social media to improve lines of communication
Promote and protect
Lesson materials obtained by Reuters included instructions on accessing and linking to social media accounts and websites of the CPP and its youth wing, while teachers were urged to try and defend the government from negative messages online.
"We must promote what's really happening, about what government has really done," said Huot Yary, head of the capital's education department, recalling instructions during the classes.
Read MoreBuild and they will come? Maybe not in Cambodia
Political analysts say the CPP is trying to counter a swell of online criticism since the last election, when the Cambodia National Rescue Party (CNRP) carved off a chunk of CPP's house majority, winning 55 seats to CPP's 68, down from 90 before.
Part of the opposition's gains were due to rapid online courting of young, urban Cambodians angered by issues like forced evictions, low factory wages and state graft.
There are concerns, however, that the government's new social media focus is not just about using it, but controlling it. The creation of Internet laws and a cyber crime task force are being considered and some critics fear the real aim is to intimidate opponents and block-out dissent.
Independent political experts forecast the 2018 election to be the closest ever in Cambodia and say the CPP has realized the battleground will now be on social media.
"It is scrambling to enter the digital age and counter the active opposition presence online," said Sebastian Strangio, a journalist and author of the book, "Hun Sen's Cambodia".
Many in Cambodia's younger generation doubt though that the government's bulked up online presence will have much sway on their opinions.
"There are all sides of information available now already, and youths know a lot - we have education," said 21-year-old university student Kim Hong.