Just a few hundred metres from the Shenzhen Bay sports complex where thousands of paramilitary police and their trucks are gathered, tourists and locals are enjoying a late afternoon stroll along the bay.

Few seem aware of the display of force that China's Government has mustered inside the tightly secured stadium nearby.

But everyone we spoke to was well aware of the unrest that has gripped the city just a few kilometres away across the water.

"I read news about Hong Kong and I think they are really out of control. The young people stopped working to protest," said a woman in her twenties named Wang, who declined to give her full name.

Initially when the protests began with up to 2 million people marching to oppose an extradition deal with mainland China, Beijing's army of censors tried to scrub any mention of it from the country's internet.

But with word spreading, China's Government abruptly changed tack.

Instead, they have made Hong Kong headline news, launching a full-blown propaganda campaign to paint the protesters as "violent criminals", "thugs" and even suggesting some were "terrorists".

The weekly violent clashes with police have been framed by Beijing as totally the fault of the "radical" protesters.

On the global internet beyond China's censorship, a fierce information war has erupted between pro and anti-China groups, with short, highly edited clips from both sides the main tool of combat.

The demonstrators who are calling for more independence from mainland China have been protesting in Hong Kong since June. ( Reuters: Thomas Peter )

"They're appealing to the Americans for democracy, right?" said a university student sipping bubble milk tea at Shenzhen Bay foreshore surnamed Zhang.

"I think foreign parties have encouraged the unrest and escalated it," he said.

"Many Hong Kong young people are abusing democracy to selfishly destroy the relationship between China and Hong Kong," he said.

In recent days, the state-directed campaign to control the narrative went into overdrive when a group of protesters at Hong Kong's International Airport mobbed two men, tied them up and humiliated them while stranded travellers watched on.

One of the victims, a reporter for the Communist Party's jingoistic Global Times, was found to have a pro-police T-shirt on him, fuelling accusations from the protesters that he was an informant trying to infiltrate the group.

But the images of young masked vigilantes shining torches in his eyes and parading him on a baggage trolley to the world's media has caused genuine anger on the mainland.

"He got beaten just because he supported the Hong Kong police. This is very different from what they claim to say about democracy and freedom. It's ridiculous," said another university student surnamed Qiu, who also didn't want to give his full name.

Hong Kong's favourite son defends the Chinese flag

Actor and martial arts star Jackie Chan said the turmoil in Hong Kong is "sad and depressing." ( Reuters: Phil McCarten )

Many mainlanders feel Hong Kongers are privileged and have long looked down on them as the poorer, oppressed cousins who lack the global affluence of the former British colony — a perception that is being reinforced by the protests.

"As mainlanders, we might be discriminated against in Hong Kong," said Qiu.

"I think Hong Kong is part of China, we're one family. We don't want to hear 'f*** off', we want to be treated fairly," he said.

In recent weeks the Chinese state media has also drummed up campaigns around the nation's flag, after protesters cut one down and threw it in Hong Kong harbour — an act that would incur jail time on the mainland.

Among the prominent celebrities joining an online campaign to "guard" the flag is Hong Kong-born Jackie Chan, who this week appeared on state television to express his patriotism and respect for it.

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Foreign interference is also a central theme of Beijing's efforts to frame the protest movement, claiming "black hands" of the CIA are stirring up the unrest.

Foreign media raises suspicions too.

Within minutes of starting interviews at the Shenzhen Bay foreshore to gauge local sentiment towards Hong Kong, a young visiting couple from Beijing declined to speak with the ABC, claiming we're out to "smear China".

They then promptly went to two patrolling members of the military police to report us, and walked away.

The pair of camouflage-clad officers filmed and followed us until we left.