An Australian democracy activist, Tran Hiep, has gone missing in Cambodia since 18 September and is feared to have been abducted by Vietnamese authorities in an act of alleged "transnational repression". He was travelling with a Vietnamese-Norwegian human rights activist, Nguyen Duc Thuan, to meet with dissident Vietnamese activists when he disappeared, raising serious concerns about the safety of political advocates operating in Southeast Asia. This incident highlights growing cross-border crackdowns by Vietnamese authorities targeting democracy campaigners and human rights defenders.

Tran Hiep, a 50-year-old Melbourne resident who founded the Australian Alliance to Combat Human Trafficking, was due to meet his wife, Chloe Dang, in Bangkok but never boarded his flight. The pro-democracy organisation Viet Tan, of which both missing men are members, claims the pair were abducted in Cambodia and forcibly taken to Vietnam, rejecting Vietnamese claims they illegally entered the country. Vietnam has intensified persecution of dissidents, with over 55 activists arrested under broad criminal laws in 2025, and there is documented evidence of increased cooperation between Vietnamese and neighbouring governments in targeting human rights advocates. Nguyen Duc Thuan requires daily insulin injections for diabetes, raising medical welfare concerns about his detention.