Over the past decade, tens of thousands of women from Southeast Asia have been sent to China by criminal networks promising lucrative jobs, only to be sold as brides - some to abusive men - as China grapples with a huge gender imbalance.
Anti-trafficking organisations said the impact of coronavirus on Cambodia's garment, hospitality and tourism sectors had fuelled a spike in "bride trafficking" this year.
"There is no work, no options, for young women, so it has become even easier for perpetrators to persuade women and their families," said Chan Saron, program manager at Chab Dai.
The charity has received reports of a new case every three days on average in 2020 - double the caseload of previous years.
Most of the victims are in their twenties but some are as young as 14, according to Saron, who said thousands of cases were likely going unreported.
Cambodian women who have returned from China often describe experiences of sexual, physical and psychological abuse, confinement, torture and forced labour.
Authorities in Cambodia have said the crime is difficult to tackle because victims' relatives are often complicit and the promise of cash - up to thousands of dollars - by criminal matchmakers is difficult to resist for poor, rural families.
"The women, most of them know the risks," Chou Bun Eng, deputy head of the Cambodian government's counter-trafficking committee, told the Thomson Reuters Foundation.
"But they still go. It's all about money, money, money," she added. "(The crime) is increasing because the perpetrators are clever, they are tricky ... promising wealth."
Bun Eng said authorities in Vietnam - increasingly a transit country for women headed to China - had got better at spotting potential Cambodian victims and stopping them reaching China.
Officials in China and Vietnam could not be reached for comment.
Hanoi-based Blue Dragon Children's Foundation, which rescues women trafficked to China, said its caseload of Cambodian victims had almost tripled this year to 19 from seven last year.
"Covid-19 has changed the trafficking landscape - for now, at least," said Michael Brosowski, the head of Blue Dragon, which was forced to temporarily freeze rescue operations in late January as coronavirus related travel restrictions took hold.
"The drastic rise in the number of Cambodians trafficked through Vietnam is a sign of how traffickers are willing to try new routes and new tricks to keep their trade going." - Reuters