Australian Kalynda Davis and New Zealander Peter Gardner met on Tinder before being arrested at a Chinese airport on drug charges, then facing the prospect of dying together in front of a firing squad.

Davis, 22, and Gardner, 25, were detained at Guangzhou airport by customs authorities, accused of carrying 36 kilograms of methamphetamine, or ice, in their luggage. The two faced a minimum of life in prison and a maximum of death by firing squad if found guilty, legal experts told News Corp Australia.

Fortunately for Davis, she was released by Chinese authorities after negotiations with Australian diplomatic staff and returned to Sydney today.

"We are happy to have Kalynda back home," said her father, Larry Davis, in a written statement. "We have always known Kalynda to be innocent of these allegations. Her return home today is a clear statement of her innocence."

Davis reportedly met Gardner on Tinder two weeks before the couple flew to China on November 5. The Australian Daily Telegraph anonymously quoted friends of Davis as saying she'd told them: "If you don't hear from me, something's gone wrong."

Gardner, so far, has not been released. Chinese authorities rarely demonstrate clemency and Davis's release is being taken as a sign that investigators believe she was unaware of the drugs the two were allegedly carrying.

This incident is just the tip of the iceberg of a massive Chinese internal battle against meth. Guangdong, the province where the pair were arrested, is in the middle of a narcotics blitz directed by the Ministry for Public Security. Last month, the _South China Morning Post _reported the crackdown had already lead to the arrests of 23,959 suspects and the confiscation of 12.1 tons of illicit substances since it started in September.

"Guangdong has the biggest migrant population in China. More than 60 percent of drug users in Guangdong were from other provinces, according to our study in 2012," Li Xiaodong of the China Association of Drug Abuse Prevention and Treatment, told the Morning Post.

Local authorities claim they have a database of 457,000 people in the province suspected of using drugs.

Traditionally, China's biggest narcotics concern has been heroin, but the last few years have seen a rapid shift towards methamphetamines. One possible reason is the development and growth of clubbing culture in the country.

A survey of club drug users in Shandong province published this year found that 96.6 percent were methamphetamine users, while only 0.5 percent used cannabis and just 3.2 percent used heroin.

Asia is the largest market for amphetamine-type stimulants in the world according to the United Nations Office on Drugs and Crime (UNODC). China accounts for 45 percent of all seizures in the region, or 16 metric tons of the drugs in total.

A bust at the end of December 2013 involving 3,000 police officers seized three tons of methamphetamine from a Guangdong town called Boshe. At the time, Chinese officials claimed the facility had supplied one-third of the country's crystal meth.