"The village was completely surrounded, they came from all sides," says one villager, who owns a corner store with his heavily pregnant wife. "I didn't even need to look outside. I knew why they were here."

The drug raids last December in the coastal village of Boshe, in the southern province of Guangdong, were unprecedented in scale. More than 3000 police and paramilitary officers were deployed, seizing three tonnes of methamphetamine with a rough Australian street value of $3 billion. Also seized were almost 150 tonnes of precursor chemicals used to manufacture the illicit synthetic drug, also known as crystal meth or ice.

China has emerged in recent years as the region's largest producer of crystal meth. And Australia is being increasingly targeted by international drug syndicates, given its willingness to pay higher prices, according to international drug control agencies and police.

"The Australian link is that the drugs are coming out of [Guangdong] and into Australia," one senior police source tells Fairfax Media.

"We are a very big receiver of drugs across the whole spectrum … we are a very wealthy country and willing to pay higher prices for our drugs.

"So unfortunately we become very much a sought-after country for drugs to go – it's just supply and demand, bottom line."

The flourishing drug trade has seen the Australian Federal Police step up its co-operation with its Chinese counterparts in an attempt to stem the tide, resulting in a series of successful busts, most notably a February seizure of 180 kilograms of ice found hidden in a shipment of kayaks into Australia.

In a statement, Guangzhou Customs confirmed to Fairfax Media that it had arrested 11 Australians on suspected drug charges this year, including one just this month. In all, it had seized 391 kilograms of drugs in 193 separate cases, arresting 79 suspects – 63 of them foreigners. If convicted, they could face the death penalty under China's strict drug laws.

Since the start of the month alone, customs officials seized more than 50 kilograms of drugs in 10 separate cases – four of which were destined for Australia.

Parcel delivery and cargo shipments are understood to be the most common method of smuggling but direct attempts are being made to traffick drugs directly through Guangzhou's international airport.

It may sound brazenly primitive, but simply walking through airport security checks remain a frequently used strategy by drug syndicates.

"It's a risky venture for trafficking. But it works. Most obviously get through or they wouldn't keep using [drug mules]," said Jeremy Douglas, the regional representative for the United Nations Office on Drugs and Crime.

On the night of November 8, Kalynda Davis and her travelling companion Peter Gardner, a New Zealand national who has lived in Sydney for years, were waiting to board Flight CZ325 to Sydney when customs officials called them into an investigations room after detecting irregularities with the two pieces of luggage they checked in.

The zippers of the bags were sealed shut with superglue, but when the bags were finally opened they were filled with 60 vacuum-sealed bags of suspicious particles, later proven to be ice. Weighing a total of 30 kilograms, the drugs would have been worth tens of millions on Australian streets, and was the biggest ever single overseas ice trafficking case brought in by Guangzhou customs.

Davis was forced to cut her long hair into a bob, and spent her birthday behind bars. Meanwhile, her parents were left mostly in the dark during the investigation, grimly aware of the consequences.

A conviction for drug offences involving more than 50 grams of methamphetamine results in three possible outcomes according to Chinese law: 15 years jail, a life sentence, or the death penalty.

"You only have to Google it to see," Larry Davis, Kalynda's father, told the Western Weekender. "I don't know what I have been feeling this past month, it is like I have been brain-dead. Think of a parent's worst nightmare and multiply it by 10, that's what we went through. I know my daughter, I know my daughter – it was just my worst nightmare,"

After a month-long investigation, Davis was abruptly allowed to return to Australia this week after Chinese police were satisfied she had no knowledge of or involvement in any smuggling plot. Gardner remains in detention awaiting a grim fate.

"After investigation, it was discovered that this drug trafficking was operated by [Gardner]," Guangzhou Customs said in its statement. "There was no evidence showing [Davis] had any subjective intention to take part in this drug trafficking crime and she has been released back to Australia."

The spate of arrests this year prompted the Australian Department of Foreign Affairs and Trade to issue a travel advisory in September highlighting China's severe drug laws and the fact that in "recent months, Chinese authorities have executed foreign nationals who were found guilty of smuggling drugs".

"Travellers have also been asked to carry goods concealing narcotics out of China," it says. "You should never carry parcels or luggage for others unless you are certain the contents are legal."

Chinese customs officials who spoke to Fairfax Media confirmed a number of Australians had been involved in alleged drug-smuggling cases in recent months, but declined to comment further.

"The Australian Government cannot override the laws and penalties imposed by another country and it is not able to intervene or interfere in the Chinese judicial process," it said in its September travel warning.

Bordering Hong Kong, the same transport links and geographic advantage that makes Guangdong a thriving trade and manufacturing hub also makes it attractive for drug syndicates.Chinese and Australian police are working to identify money flows from Australia into China and Hong Kong that may be proceeds of crime.

Douglas says meth produced in China now makes up half the total seized across the region.

"Basically the situation is you have the availability of high-quality chemicals, very skilled chemists and also a growing domestic [drug] market," says Douglas. "Guangdong is a hub for trade so you can use trade channels out of the region to reach end markets."

Larry and Jenny Davis' nightmare began when they realised their daughter Kalynda had not boarded her scheduled flight to Sydney and had not logged into her Facebook account. Soon after filing a missing persons report, they were given the chilling news that she was in detention in Guangzhou, under investigation for trafficking a commercial quantity of ice.

"She only had carry-on luggage, that's all she had, and she was just approached by authorities and asked to come back to the office. Then she found out what was happening and was taken to the detention centre," Mr Davis told the Western Weekender. He also revealed that his daughter had initially made plans to visit only New Zealand, but that her trip to China with Peter Gardner, whom she reportedly met weeks earlier through an online dating app, was a late addition to the itinerary.

Her long hair was cut into a bob, and she spent her birthday in jail. Meanwhile, her parents were left largely in the dark during the investigation, grimly aware of the consequences. A conviction for drug offences involving more than 50 grams results in three outcomes according to Chinese law: 15 years jail, a life sentence or the death penalty.

"You only have to Google it to see," he told the Weekender. "I don't know what I have been feeling this past month, it is like I have been brain-dead. Think of a parent's worst nightmare and multiply it by 10, that's what we went through. I know my daughter, I know my daughter – it was just my worst nightmare."

Ultimately the nightmare ended when she was cleared of any suspicion after a month-long investigation. "When we hit the tarmac in Sydney, we both just cried," he said.

The family also released a statement after Kalynda's release to the family of Peter Gardner, who remains in jail, facing a potentially much grimmer fate.

"To the family of Mr Peter Gardner, we will continue to pray for Peter and your family. You are always in our thoughts."

Police dub Boshe, in Lufeng County, a "fortress" of illicit meth production, with families producing industrial quantities of meth in their houses and makeshift factories practically in full view, having bribed local police and village-level Communist Party officials for protection.

"Once you went outside the house, the smell was so strong, my eyes would sting and my nose would go runny," says Cai Mulong, a 42-year-old father of four who makes hand-made noodles and repairs motorcycles for a living.

"But we didn't dare to say anything to them, or anyone else."

Of nearly 200 arrests in Boshe, the prize scalp was that of Cai Dongjia, the village's party head, who oversaw the racket in the otherwise unremarkable coastal village of 10,000 people, most of whom share the same family name.

The scale and public nature of the raids were designed as a shock and awe campaign to crack down on the rampant production of synthetic drugs in southern China. Last month, authorities in Lufeng – an infamous drug hub which police say produces one-third of China's ice – invited local media to witness the ritualistic burning of 400 tonnes of precursor chemicals seized over the course of the year.

It comes amid another much-publicised takedown of a Guangzhou meth boss with the street name "Professor Xu", who was swiftly christened China's Walter White – a reference to the high-school teacher turned meth cook protagonist of US crime drama Breaking Bad, which enjoyed a loyal online cult following in China during its run.

Synthetic drug manufacturing is mobile by nature. As long as the precursor chemicals are readily available, meth labs can spring up elsewhere after each bust.

But the end of its drug-fuelled economy has left Boshe a shadow of its former self. Like many Chinese villages, it is populated mainly by women, the young and the elderly. The village's younger men – those who have not been arrested – have mainly left to find work in larger towns and cities.

Double-storied luxury villas, some only partly built, are left abandoned. Local shopowners remark how much business is falling.

Cai Mulong, the 42-year-old noodle vendor, says it was fortunate his family did not fall into the drug trade – the syndicate ostracised him because of his failing eyesight and hearing impairment.

To supplement the family's meagre income, Cai's teenage daughter earns the equivalent of $4 a day by folding joss paper, burnt as an offering for the dead.

Other families, she says, have sent their children to work with the drug syndicates in a desperate attempt to alleviate poverty.

For Cai, the father, his health issues have had a silver lining.

"It doesn't matter if I have to work harder to make ends meet. What's the use in making money so quickly?" he says. "When I sleep at night, I sleep well."