A park in Beijing has installed toilet paper dispensers with facial recognition to stop visitors from taking too much loo roll, media reports say.

Machines at the Temple of Heaven park scan visitors' faces before dispensing a fixed length strip of paper.

The tourist attraction is reportedly frequented by visitors who take large amounts of loo roll home.

It has reignited debate over the lack of social graces among some Chinese.

Flushed with success

The newspapers Beijing Wanbao, Fazhi Wanbao and Beijing News reported that park officials have installed six machines at its public bathrooms in a half-month trial, with staff on standby to explain the technology to visitors.

The machines, placed at the average heights for men and women, dispense strips of toilet paper measuring about 60 to 70cm (24 to 27.5 inches) to each person, said reports.

They will not dispense more paper to the same person until after nine minutes have passed.

"If we encounter guests who have diarrhoea or any other situation in which they urgently require toilet paper, then our staff on the ground will directly provide the toilet paper," a park spokesman told Beijing Wanbao.

The park also upgraded the toilet paper's quality from one-ply to two-ply.

Repeated calls by the BBC to the park's media department were not answered. A representative who answered the park's main line declined to answer questions.

Earlier this month, Chinese media reported that visitors to the Temple of Heaven park's toilets were taking excessive amounts of toilet paper, some of whom were seen stuffing their bags.

The park has been aware of this problem for years, which began shortly after it started dispensing free toilet paper in 2007.

It has put up posters as well as broadcast messages on its public announcement system exhorting visitors to use less paper.

The trial appears to have had initial success - the park told Beijing Wanbao that the daily amount of toilet paper used in its toilets has gone down by 20%.

But it has also had teething problems. Reports said that the machines, which take between 10 and 30 seconds to scan a face, had caused delays and confusion among some visitors who needed staff assistance.

Beijing News said that two machines had also broken down during a recent visit over the weekend.

'Use paper economically'

The case has both amused and exasperated Chinese netizens, who have condemned those raiding the park's toilet paper supply.

"Several low-class people have forced the rest of society to undertake a high-cost operation," said one user.

"This is so ironic, the paper in public toilets is meant to serve all in society, now we have to use technology to regulate it," said another.

Earlier this month, the Beijing Municipal Administration Center of Parks launched a campaign on Weibo called "Use Paper Economically, Spread Civility".

Residents were asked to take a pledge to "take appropriate amounts of toilet paper with no wastage" from public parks.