The Chinese Communist Party's paranoia is on full display for its congress in Beijing in a security squeeze extending from police swarming Tiananmen Square to elderly sentinels watching street corners.

The capital has 1.4 million "public order volunteers" -- retirees, street cleaners, firemen and low-paid private security guards -- on the lookout for anything that could upset the sensitive gathering, even in the quietest residential neighbourhoods.

But despite their patriotic armbands, many grumble about being roped in as foot soldiers for China's massive police state.

"Volunteer? They made me volunteer," said Zhang Weilin, 25, a security guard at a central Beijing shopping mall who wore a camouflage jacket bearing a "US Army Airborne" patch and that was a size or two too large.

"My security company gave us the uniforms and made all of us (other security guards) volunteer during the congress," he said.

Increasingly worried about rising social unrest and acutely aware of public unhappiness over a lack of democracy, Chinese authorities have dramatically escalated the state security apparatus under President Hu Jintao.

At the end of the congress next week, Hu is widely expected to hand leadership of the party to Vice President Xi Jinping after ten years in power.

Under Hu, security budgets have exploded -- $111 billion was allocated in 2011 for "stability maintenance", exceeding China's stated defense budget.

Authorities frequently buttress security by tasking ordinary citizens with maintaining order in their patch and reporting potential threats to the Communist regime, particularly during important events like the congress.

"If we see anything out of the ordinary, like a petitioner trying to protest, we report immediately to the neighbourhood committee, who calls the police," said retired teacher Huo Huihua, watching a Beijing street corner.

Under an age-old system from imperial times, Chinese across the country are officially granted the right to petition to Beijing authorities against local injustices.

However, petitioners and rights groups claim complainants are routinely jailed, beaten, or otherwise persecuted into silence. Rights groups say petitioners are being detained and ejected from the city during the congress.

"It doesn't matter if the petitioner has a legitimate beef or not. That will be up to the police to decide," said Huo, adding a sad grimace that acknowledged routine police brutality.

Zhang Yaodong, a petitioner from Henan province, was beaten to death by unknown thugs on Tuesday ahead of the congress, a rights group has said.

Beijing police refused comment to AFP. Such incidents are common in China and often trigger violent demonstrations.

Although AFP reporters have witnessed numerous petitioners being dragged by police since the congress began, none of the nearly 20 "public order volunteers" interviewed by AFP said they had seen anything that merited a report to police.

The security clampdown in Beijing has many of its practical-minded residents involved in the effort wondering why none of the huge security spending has trickled down to them.

"If any 'stability maintenance money' is handed out, it will surely go to the neighbourhood committee, we will never see any of it," said a retired worker named Chen.

Instead, rewards for "volunteers" included uniforms, jackets, soap powder and cooking oil in exchange for the hours spent on street corners in the chilly November air.

Dissident Bao Tong said the huge domestic security build-up of recent years indicates the Communist Party has lost its ruling legitimacy.

"No country in the world makes its own people the biggest enemy," Bao, who was the highest official jailed following the 1989 Tiananmen Square democracy protests that were suppressed by the army, told AFP before the congress opened.

"In a republic, the people should be the masters. 'Stability maintenance' takes the people as the enemy. This is an insult and a disgrace," he said.

Chen Huili, a house cleaner who says she was pressured into acting as a neighbourhood sentinel, has her own reasons for grumbling.

"I didn't volunteer. My company is making me do this," said Chen, as she swept up cigarette butts in a Beijing housing complex wearing a red "public order volunteer" arm band.

"They didn't give me anything but extra work to do."