Phnom Penh, Cambodia | Looking more avuncular than authoritarian, Cambodian premier Hun Sen crouches for a selfie for his Facebook page with young scouts -- part of a social media blitz selling the strongman's cuddlier side as he seeks to extend a 30-year grip on power. 

The 63-year-old, a wily political survivor who defected from the Khmer Rouge to oversee Cambodia's rise from the ashes of war, has vowed to remain prime minister until he is 74.

To do so he will need the support of Cambodia's youth -- a tech-savvy demographic whose votes may well be decisive in the next election, slated for 2018.

Two thirds of Cambodia's 15 million population are aged under 30. Like their contemporaries everywhere they are avid users of social media -- a sphere Hun Sen has until recently viewed with suspicion.

In 2013, young Cambodians voted in droves for the opposition, wearied by the endemic corruption, rights abuses and political repression seen as the hallmarks of Hun Sen's rule. 

A self-confessed digital dinosaur, Hun Sen has in recent months launched himself online with an arsenal of new media tools. 

He has just debuted a 'Hun Sen' App for Android and Apple phones -- complementing a new personal website -- to allow the public to "receive news about me quickly".

Meanwhile his official Facebook page, minted in September, already has more than 1.9 million 'likes'.

"Wherever technology goes, we must be there too," Hun Sen said recently, also revealing in a Facebook post that he carries five smart phones to stay connected with his countrymen.

Opposition leader Sam Rainsy, whose Cambodia National Rescue Party (CNRP) say they were denied a majority in 2013 by vote rigging, has more than two million 'likes' on his official Facebook page and has long embraced social media to spread his message. 

With under three years to the next election, the battle for power looks poised to play out online.

- What's the game? -Sebastian Strangio, author of a recent book on the mercurial premier, says Hun Sen's belated embrace of technology once more illustrates the "tactical flexibility" which has kept him in power over the decades.

"Cambodia’s old political battles have simply shifted online," he added. 

But Hun Sen's online forays have received a mixed reception from his target audience.

"Awesome for an ex-bumpkin... but nothing special for young generation Khmers! They were there long before him," one Facebook user posted in English on the premier's page. 

Others say the strategy is working, bringing the premier into the daily lives of young people.

University student Kea Ny, 26, told AFP many of his peers have changed their attitudes on the back of his social media outreach work.

"Among 10 of my friends, seven of them support him now. Before they all had negative feelings towards the prime minister," he said.

While it good news for Hun Sen's social media team, critics say the move is merely another feint by a master manipulator renowned for cracking down on freedom of expression. 

The former communist cadre already leans heavily on pliant courts and security forces to keep rivals in check.

His government is now pushing for a cybercrime law, which critics fear will be used to target dissent. 

Rainsy is currently in self-exile after a slew of criminal charges were brought against him and other core CNRP officials, which they say are politically-motivated. 

An opposition senator has been also arrested over posting a doctored treaty of a highly-sensitive border area with Vietnam on Facebook. 

Rainsy has been charged with being accomplice in that case.

Fearing arrest over the post, three other members of Rainsy's social media team have fled Cambodia.

Others were not so lucky -- including those in the age range the ruling party hopes to woo.

In August, a 25-year-old student was charged with incitement to commit a crime over an alleged Facebook post calling for a "colour revolution" in the country.

Another 25-year-old was charged in early January for posting "insults and threats" on Hun Sen's Facebook page. 

If convicted, he faces up to two years in jail. 

"He (Hun Sen) is taking to social media to show his softer side," Cambodian political analyst Ou Virak told AFP.

"The sinister flipside is of course an increased monitoring of social media, epitomised by the cybercrime law." 

Hun Sen's political rivals say they are relaxed by his leap into the digital age.

"We focus on issues that the government does not pay any attention to," Chheng Sorphorn, 29, a member of Rainsy's social media team, told AFP.

The CNRP's posts link to hot-button subjects such as land grabs, poverty, workers' demonstrations, he added, explaining those draw the real support of the majority of Cambodians.

That leaves the CNRP bullish over its prospects at 2018 polls.

Yet few expect Hun Sen to cede power without a fight.

"If Hun Sen and the CPP sense they are losing their popular mandate they may resort to repression and violence... to stay in power," warned Cambodia expert Carl Thayer, a professor at the University of New South Wales in Australia.