It's nine in the morning and the gaming tables are still going strong. As croupiers take bets from the overnight die-hards, several exhausted gamblers sleep nearby, one still clutching a wad of betting slips.

Welcome to the Kings Romans, a sprawling casino complex topped by a giant golden crown that bursts into view from a sleepy river bank on the Laos' side of the Mekong River.

The Chinese-owned casino in Ton Pheung district, Bokeo, is the centrepiece of a 10,000-square metre "Golden Triangle Special Economic Zone" set up by communist-ruled Laos with investment from its giant neighbour.

The other Golden Triangle nations, Thailand and Myanmar sit just across river, an intersection that has long hosted illicit activities -- from drugs and human trafficking to weapons smuggling and the sale of rare species.

The casino is an attempt by the Laos government to cash in on an activity that is banned in China yet loved by its people: gambling.

And the good times are rolling as a Chinese crackdown on gambling and other vices pushes pleasure-seekers to more permissive nations nearby.

The two-storey Kings Romans casino is dwarfed by its rivals in the regional gambling hub of Macau and even in Southeast Asian neighbours Cambodia and Vietnam.

But -- open seven days a week, 24 hours a day -- Kings Romans receives a steady stream of Chinese gamblers who have made their way south with pockets and briefcases filled with cash.

"Chinese players really are among the greatest gamblers in the world," a hostess responsible for welcoming customers enthused to AFP during a recent visit.

"They can stay one or two days at the same gaming table non-stop, it's incredible," she added, unwilling to give her name in a zone dominated by murky interests and where discretion is the watchword.

- Slice of China -

Venturing inside the SEZ feels like stepping into mainland China. The clocks are all set to Beijing time, Mandarin and other Chinese dialects are commonplace and the main currency is the yuan.

Few of the employees are Laotian. Most are Chinese or from Myanmar.

For impoverished, landlocked and isolated Laos, the zone is a much needed source of income.

Chinese money runs throughout the Laos economy. It is the nation's biggest investor with rail, roads and hydropower among China's main interests.

But observers say the inflow of cash has come at a cost -- including serious environmental damage and the displacement of landless poor to make way for mega-projects.

Observers say the SEZ has now become a place to wash dirty money from China as well as local criminal networks, with fears the 99-year lease will only cement that status.

The Golden Triangle has long been known for its drug production. In previous decades it produced some of the world's most sought after heroin.

In more recent years many of the drug syndicates have switched to lab-produced crystal meth and other synthetic highs, according to a recent United Nations Office on Drugs and Crime (UNODC) report.

"Cash-based commercial activities such as casinos, currency exchange shops or even just restaurants offer better opportunities to introduce in the legitimate economy money obtained through illegal activities," warns Giovanni Brossard, from the UNODC.

Laos has moved to crack down on money laundering, Brossard notes, with laws against the crime and by setting up a financial intelligence unit within the country's state bank.

"Yet so far no single money laundering case has made it to court," he says.

- 'Sauteed tiger meat' -

Alongside gambling a whole host of other bacchanalian industries have sprung up to cater to punters looking to play away from prying eyes in their homelands.

Sex workers openly ply their trade on the sidewalks or at the myriad massage parlours.

"People love to come here with friends and book private rooms," explains a Chinese member of staff at a disco near the casino.

"Most are men and they bring in girls."

Conservationists say the SEZ also caters to those with illegal culinary tastes.

A recent probe by campaign group the Environmental Investigation Agency (EIA) found visitors could openly buy products from endangered species including tigers, leopards, elephants, rhinos and bears.

Restaurants offered sauteed tiger meat, bear paws and live pangolins on their menus.

"One business kept a live python and a bear cub in cages, both of which were available to eat on request," the NGO's investigators found.

During AFP's visit in early April, the businesses allegedly unmasked by the EIA investigation were no longer open.

As a signatory to the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), Laos is supposedly committed to stopping illegal wildlife trafficking and clamping down on the illegal ivory trade.

But the convention is widely flouted.

Animal rights workers say both Laos and China have a responsibility to ensure the special economic zone does not become a haven for the illicit wildlife trade.

"The Chinese businesses and consumers are exploiting weak enforcement in Laos, but the Laos government can't pretend they are ignorant of what is going on," says Debbie Banks, from EIA.